Abstract
Over the last few years, many classifications have been proposed for functionally graded materials (FGMs). In this Paper, critical review of different available classifications for FGM based on their physical, structural and manufacturing characteristics are presented. Advantages and limitations of each fabrication method for use in a given application is correspondingly considered. In addition, new classifications based on gradation control and accuracy, residual stresses, specific energy consumption, environmental impact evaluated throughout the complete life cycle and manufacturing costs are proposed. These classifications mainly reflect the needs of both FGM designers and industrial manufacturers. Based upon the presented classifications and the recent advances in analysis and production techniques, new major directions for FGMs research are proposed.
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1 Introduction
Many applications such as aerospace, automotive, power generation, microelectronics, structural and bioengineering demand properties that are unobtainable in conventional engineering materials [1, 2]. These applications require mutually exclusive properties to have resistance against thermo-mechanical stresses as well as chemical stability. The need for property distributions are found in a variety of common products that must have multiple functions, such as gears, which must be tough enough inside to withstand the fracture but must also be hard on the outside to prevent wear [3]. Similarly, a turbine blade should also possess a property distribution. The blade must be tough to withstand the loading, but it must also have a high melting point to withstand high temperatures on the outer surface [4].
Conventionally, surface treatment or hardening techniques were used to reach the required properties. However, there were always concerns about the properties at the interface or the adhesion of the surface layer to the substrate materials [5]. In addition, the treated surface layer may not be sufficient to achieve the required product life [6]. Although alloying can be used to partially improve the performance in such cases, there is a lot of limitations related to material solubility due to thermodynamic equilibrium. Likewise, alloying of two materials with wide apart melting temperatures is difficult or even impossible. Powder metallurgy represents an excellent method of producing parts with conflicting properties than conventional alloying [7]. Another method to achieve tailored material properties is the use of composite materials. Both matrix and reinforcing materials possess distinct physical and chemical properties. Composite materials offer excellent combinations of conflicting properties. Unless the material is laminated, the properties of composites are equally distributed over the entire material giving a homogeneous behaviour on the product level. This cannot be used to achieve the required gradient in the applications mentioned above [8]. Although laminated composites can produce very narrow but discrete change of properties across the thickness, they suffer from inter-laminar shear stresses and discontinuity at the interface.
In 1972 the general idea of structural gradients Functionally Graded Materials (FGM) was initially proposed for composites and polymeric materials [9] to imitate the structure and behavior of natural materials like bones, teeth [10] and Bamboo trees [11] etc. The concept of FGM was first applied in Japan in 1984 during the design of a space shuttle [12]. The objective was to manufacture the body from a material with an improved thermal resistance and mechanical properties by gradually changing compositions to withstand severe temperature difference of 1000 °C. Figure 1 illustrates the historical progress from pure metal to functionally graded metals.
FGMs exhibit many advantages compared to conventional alloys and composite materials. FGMs introduce means for controlling material response to deformation, dynamic loading as well as to corrosion and wear [13], etc. Furthermore, they give the opportunity to take the benefits of different material systems e.g. ceramics and metals [14]. In addition, biocompatibility of some FGMs increase their suitability as bone replacement. FGMs can also provide a thermal barrier and can be used as high scratch resistance and reduced residual stress coating [15]. Similarly, FGMs can be used as a high strength bonding interface to connect two incompatible materials [16]. Figure 2 illustrates the possible variation of properties in conventional composites compared to FGMs. A single FGM can be obtained by a single dispersed constituent/phase that is not uniformly distributed within the matrix compared to conventional composites, while more than one constituent/phase in the case of double FGM. The continuous gradient is obtained in all cases, depending on the change distribution density among the used constituents/phases and the matrix.
FGMs were initially classified by researchers under conventional composite materials depending upon the used combinations of constituents [17]. There exist many possible material combinations that can be used to produce FGMs. Metal–metal, metal–ceramic, ceramic–ceramic or ceramic–polymer [18] are the most common as shown in Fig. 3 [17, 19]. Over time, and because of the development of more applications and technologies to produce FGMs at different scales, different classifications appeared. In the third section of this paper, six conventional classification criteria were presented to classify the FGMs based upon: state during processing, FGM structure, FGM type, nature of FGM gradient, main dimensions, and field of FGM application [20, 21]. With the help of these aspects or classifications, the fabricated FGM can be always described. However, these classifications are of little help to FGM industrial producer in the selecting the appropriate fabrication technique that fulfills both the technical requirements of the designer (e.g. shape complexity, accuracy, minimum residual stress), and the economic requirements of the industry (e.g. productivity, minimum energy, minimum cost, lower environmental impact). The classifications that will be introduced in this paper aims at providing some guidelines for the industrial manufacturer to find the proper fabrication technique that meets both the technical and economic aspects.
2 FGM production methods
Quite a large number of well-known techniques and fabrication routes are widely used for the production of FGMs as summarized in Fig. 4. These ranges from old and simple to advanced and complex techniques and covers various physical and chemical principles. FGM production techniques include centrifugal casting, powder metallurgy, plasma spraying, chemical and physical vapor deposition (CVD/PVD), lamination and infiltration methods, in addition to the family of solid freeform fabrication (SFF) or additive manufacturing (AM) with its subcategories. Nowadays, various kinds of materials can be used in AM processes, including metallic material in LENS and DMD, polymer material in FDM and SLA, and biological material in inkjet printing and micro extrusion [23]. Many publications which focus on the description of the details of the different production methods and discuss their technicalities, advantages, limitations, applications and research trends are found in literature [3, 24,25,26,27,28,29,30,31,32]. It is clear that most research work focused on experimental mechanical characterization (esp. tensile and hardness) [33], wear rate prediction [34] or thermal properties evaluation [35]. Very few research groups are considering numerical simulation of FGMs. This may be due to the high degree of complexity related to the modelling of the different constituents and their properties, modeling of interfaces and the gradual change of structure. Description of FGMs production techniques is not within the scope of the current work. However, the main characteristics, advantages and limitations of available manufacturing families and processes are of great interest for the purpose of process classifications.
Table 1 summarizes these aspects and lists a number of recent publications which were mostly concerned with the optimization of FGM production parameters or aimed at the achievement of specific properties. The number of publications reflects the trends of scientific concern and the market importance of some manufacturing techniques. These cover a wide range of product sizes, complexity, durability, productivity and cost. Centrifugal casting technique that suits more bulky and simple products is still in competition with high quality powder metallurgy processes used for manufacturing of special moderate complexity parts, and with advanced additive manufacturing techniques (AM|) which proved to excel in producing relatively small complex prototypes. The information extracted from the listed sources is used to introduce the main technical features of each of the available manufacturing process to the reader. This gives a different perspective that helps in understanding the reason behind the need for new classifications that differs from the conventional classifications presented in the next section.
3 Conventional classifications of FGMs
3.1 According to the state during FGM processing
Based on the state of FGM processing, methods can be broadly classified into solid state processes, liquid state processes and deposition processes. Figure 5 lists the different processing methods falling under these categories [36]. There exists a large number of research work covering all processing states within different FGM production techniques. Deposition methods represent highly advanced technologies that are used for high accuracy and small products. Liquid-state processes are usually used for large products of relatively lower property control, while solid-state-based FGMS are utilized for highly stressed thermo-mechanical components [37]. The production of FGM by different routes and in different states affects the characteristics of the final product according to the thermal influences, mechanical loading, pressure and inertia forces taking place during manufacturing.
3.2 According to FGM structure
FGMs can be generally classified into two main groups: continuous and discontinuous graded material as shown in Fig. 6 [121]. In the first group, no clear zones or separation cut lines can be observed inside the material to distinguish the properties of each zone. In the second group, the material ingredients change in a discontinuous stepwise gradation which is known as layered or discrete FGM. Continuous and discrete can further be classified into three types: composition gradient (Fig. 6c, f), orientation gradient (Fig. 6d, g), fraction gradient (Fig. 6e, h). A further subgroup can be obtained by considering size change in any of the cases (e.g. grain size coarsening or different particle sizes) [45].
Fraction gradient type can be obtained by utilizing centrifugal force through the use of centrifugal casting process [63]. Centrifugal and repulsive forces act on the particles [27], which are dispersed into the melt. There is also the gravitational force, but in almost all cases, gravity is very small with respect to the centrifugal force and can be neglected [32]. Theoretically, shape gradient can introduce a well-tailored property distribution. However, the process of fabricating the reinforcing/dispersed phase with the necessary accuracy and the placement of the shaped constituent is very sophisticated and cost intensive from manufacturing point of view. Powder metallurgy represents one of the important method of producing FGMs containing shape gradient [121].
The properties of FGMs containing orientation gradient change as a result of a change in particles orientation, not due to a phase ratio or size change. There are different methods that can be used to achieve orientation gradient in FGMs. Subjecting the molten metal to strong electromagnetic fields can help in reorientation of the reinforcing particles in the molten metal slurry. The electromagnetic forces have different roles depending on the type of the produced functionally graded (FG) composite. In the production of reinforced ceramics by liquid routines [122], they may be used to drive the ferromagnetic particles to the required position and with required orientation. On the other hand, electromagnetic forces are used to affect the solidification of the liquid matrix in MMC [32]. An appropriate thermal control of die cooling with the aid of electromagnetic fields governs the magnitude and direction of the solidification velocity [123] and help in obtaining the graded structures in MMCs [124].
Size gradient FGMs are easily achievable based on the fundamental phenomena of flotation and sedimentation. Gravity and squeeze casting processes make use of these phenomena along with gravitational forces for the production of particle reinforced composites. Through manipulation of particles’ sizes/masses and surface properties, particles can be distributed in the molten metal/alloy according to the magnitude and the direction of the resultant force [3]. Centrifugal and repulsive forces acting on the dispersed constituent also have an effect on the resulting FGM structure.
3.3 According to the type of FGM gradient
FGMs can be generally classified into three different groups of gradient: composition, microstructure, and porosity as shown in Fig. 7 [125]. The composition type of FGM gradient depends on the composition of the material, which varies from one substance to another, leading to different phases with different chemical structures. These different phases of production depend on the synthetic quantity and the conditions under which the reinforced materials are produced [41]. During the solidification process, the microstructure type of the FGM gradient can be achieved so that the surface of the material is extinguished. In this type, the core of the same material can cool slowly, helping generate different microstructures from the surface to the inside of the material [126, 127]. With the changes in the spatial location in the bulk material, the porosity type of FGM gradient in the material changes [128]. Powder particle sizes can be measured by varying the pore particle sizes used during gradation at different positions in the bulk material [129].
3.4 According to the FGM scale and dimensions
“Thin FGMs” are manufactured by different methods like physical vapor deposition (PVD) [109], chemical vapor deposition (CVD) [130, 131], thermal spray deposition [132] and self-propagating high temperature synthesis (SHS) techniques like laser cladding (Fig. 8) [133,134,135], while “Bulk FGMs” are manufactured by powder metallurgy [136, 137], centrifugal casting [138, 139], solid freeform techniques [140], gravity settling. Thin FGMs ranges between 5 nm and 500 nm [141, 142] and may be extended to the micro-meter range (e.g. 1–120 μm thick deposited layers [130, 143]. In thick FGMs, gradients can cover 5–350 mm [26, 56, 144]. Also, the gradient of FGM can developed along one, two or even three different directions.
3.5 According to the nature of FGM gradation process
Another classification of the gradation process divide the FGM production to constructive and transport processing [145]. The first category assumes a layer by-layer construction starting with an opposite distribution in which the consecutive gradients are exactly constructed [146]. While in the second category, gradients within the structures are dependent on the physics of transport method (e.g. fluid flow, diffusion or heat conduction) [69, 147]. The advantage of constructive methods is the ability to fabricate unrestricted number of gradients. Advances in additive manufacturing during the last two decades have proved that constructive gradation processes are technologically and economically feasible, especially for prototypes and small batch production (Fig. 9), even with constituents that are not entirely compatible or homogeneous in nature [36]. Additive manufacturing (AM) techniques, offer additional advantages in form of accuracy and repeatability to reproduce the designed gradients and properties [148].
3.6 According to the field of application
As described in the introduction section, FGMs were found and used in either severe operating conditions or very sensitive application. Examples include heat exchangers, heat resisting elements in space crafts or fusion reactors as well as for biomedical implants. [28, 149, 150]. Various combinations of the ordinarily incompatible functions can be implemented to create new materials for aerospace, chemical plants, nuclear energy reactors, etc. [22, 151, 152]. According to area of application, FGMs can be classified into biomaterial [125, 153,154,155], aerospace [156,157,158], automotive [159, 160], defense [161, 162], cutting tools [163], nuclear reactor [164], smart structure [165], turbine blades [166] and sports equipment [167]. Figure 10 represent an overview of the classification according to the major fields of applications.
4 Proposed classifications for FGM processing methods
The classifications which have been introduced in previous sections are mainly based on the nature of the constituents and their physical characteristics (size, relative positioning and density) to suit a specific application. However, in most fabrication processes, there is no concrete design methods that can be followed to realize a specific property gradient. In the following subsections, widely used FGM production techniques will be classified from designer or manufacturer point of view. The classifications will consider some technical aspects such as the realizable the complexity of product form and wall thickness, the degree of control on gradient, the developed residual stresses due to the FGM production method, the specific energy consumption and the related environmental impact, in addition to the economic aspects which will be represented in form of evaluation of the equipment and total production costs. These classifications aim at providing guidelines for the manufacturer to help them selecting the FGM manufacturing process which almost meets their technical requirements and provide answers to their economic-related questions.
4.1 Classification according to the achievable complexity of shape
Complexity of shape plays a vital role in the selection of the FGM manufacturing process [168, 169]. The complexity of shape may be quantified or classified by the ability of the manufacturing method to create a complicated geometries in distinct directions or by the possible achievable directions of gradients in the space [169,170,171,172]. A perspective for classification according to complexity of product shape is represented in Fig. 11.
4.2 Classification according to the degree of gradient control
FGMs can be classified according to the degree of control on gradient or the accuracy of reinforcing phase distribution into three main categories: high degree of process control, moderate degree of process control and low degree of process control, as shown in Fig. 12 [100]. Gradient control is defined as the degree by which the predesigned property change governed by the particle or reinforcement concentration along the direction of gradient is achievable. High control methods can realize the predesigned property gradient with an accuracy of more than 90%, as shown in Fig. 13 [173]. The high grade of control is mainly achieved by the capability of the process to place the reinforcing constituents. This is more realizable in solid state processes than in liquid state ones. Although low control techniques provide smoother variation of properties compared to moderate control methods, the control of production parameters in the first group is much more complex due to the considerable number of involved parameters as well as their interactions. For example, the range of particle size in powder to be used for powder metallurgy should vary from 4 microns to 200 μm [174]. In addition, there is a wide range for the variability of each parameter such as grain size of particles or the viscosity of matrix material at different points inside the FGM during solidification [175]. Moderate and low control methods are not normally predesigned to achieve a specific property gradient and depends mainly on experience of the manufacturer or trial and error. The variation in the resulting gradient range between 50 and 60% in the low accuracy group and increase to 80% in the moderate accuracy group. Some examples of realizable gradients which can be achieved using both groups are represented in Figs. 13 and 14.
4.3 Classification according to the effect of residual stresses
Different FGM production techniques result in various levels of residual stresses that develop during manufacturing. Table 2 shows the residual stress value in the different production processes for thermal expansion (CTE) coefficients and large changes in production temperature. Figure 15 represents a perspective for classification FGM production methods according to the level of residual stresses. Although stress relief heat treatment is commonly advised to remove or reduce the influence of residual stresses, there are no investigations which are concerned with the post-treatment of FGM products to optimize the amount of residual stresses [176,177,178,179,180].
4.4 Classification according to the energy consumption and environmental impact
Energy consumption has become a very critical factor while selecting a manufacturing technology. Detailed analysis of energy consumption distribution over the process stages (e.g. heating, feeding, pressing, removal, etc.) in addition to the energy needed for preprocessing of input materials and post-processing of products have been studied by many research groups [23, 187,188,189,190]. Specific energy consumption (SEC) is widely used for the comparison of different processes or process stages with respect to the produced mass (or volume in some cases). The evaluation of energy consumption has been extended in some studies to include the energy consumption estimate during the product life. An example of comparing the energy consumption of electron beam melting (EBM) technique to conventional machining is given in Table 3. This type of life cycle analysis (LCA) is used to evaluate the Global Warming Potential (GWP) and hence the environmental impact of the production process. Some investigations and industrial studies considered the comparison of some manufacturing processes that suits FGM production with conventional forming and machining processes and evaluated SEC and GWP for studied groups and processes.
Due to the difficulty to establish a general evaluation formula, models with different variables and weights were usually formulated and evaluated with the help of some case studies. For example, [191] compared SEC of various conventional forming techniques (casting, injection molding) and machining processes (milling, turning, drilling, grinding) to six different additive manufacturing techniques. An example of the presented series of SEC charts is shown in Fig. 16. The study also presented some beneficial pie charts showing the energy consumption distribution over the stages of each process.
Based upon the presented results, attention should be paid to the use of AM techniques as a powerful FGM production technique due to its very high SEC. In a recent study, Azevedo et al. [192] stated that “Additive manufacturing is the only process besides press and sintering whose environmental impact has been studied in the literature”. In a recent publication, Liu et al. have evaluated the GWP impact of AM techniques as shown in Fig. 17 and proved that the optimization of process parameters can result in an improved GWP.
Ingarao et al. [193] investigated the environmental impact of AM techniques in comparison to conventional forming and machining techniques. The in-depth investigation included pre- and post-manufacturing stages in a detailed LCA analysis. Ecopoint is selected as single point indicator for environmental impact quantification, while CO2-eq was also selected as a single indicator for Global Warming Potential (GWP). Results revealed that AM could not be identified as an environmentally friendly solution. Even with scenarios assuming 50% weight reduction, conventional methods are still preferable. The change of “breakeven ecopoint” with the geographically-dependent variability of aluminum production is always in favor of forming processes for quantities more than 137 products. A case study of car component with AM optimized geometry showed that AM still does not result in more green choice. The breakeven Ecopoint is reached after about 2 millions of km drive distance! Figure 18 shows the high environmental impact of AM compared to conventional machining. It should be also noticed that processing cost is the decisive factor in AM processes due to the high energy demand.
According to the available information, models and discussion, FGM production methods can be broadly classified into low SEC, moderate SEC and high SEC processes. The different processing methods falling under these three categories are listed in Fig. 19. The data used for this classifications is collected from [190,191,192, 195]. The power ranges for some industrial equipment available on market is summarized in Table 4.
4.5 Classification according to the total process cost
Cost plays a significant factor in the selection of FGM manufacturing process. Cost factors include both fixed costs (which depends mainly on the used technique, required equipment and tooling as needed automation) and variable costs (which varies with many technical aspects including the used materials and processing parameters which greatly influence the energy consumption). The feasibility of a given production process should be always evaluated according to the planned production quantity or the breakeven volume. A number of research work and industrial reports considered the comparison of cost for different techniques which are suitable for FGM manufacturing, or compared them to conventional forming and machining processes. For example, a comprehensive study of costs and cost effectiveness of additive manufacturing was published by National Institute of Standards and Technology [190, 196, 197]. The study showed that the greatest AM cost driver is the initial investment in equipment. Initial machine costs account for 45–74%, while tooling account for only 5% of the total production cost, as shown in Fig. 20. In comparison, injection molding dies accounts for more than 90% of the manufacturing costs. According to a 2015 study published by the International Cost Estimating and Analysis Association, the AM materials’ costs are nearly 8 folds of those used in conventional forming and machining on a per-weight basis. However, the lower material consumption in case of AM compensate the high material costs so that the materials cost accounts for 18–30% of the total production cost.
Experience of the manufacturer plays an important role at this point, where some rule of thumb exists for different processes. For example, PM products are economically feasible only for small parts with weights between 20 and 200 g produced in mass production in order of 104–105 products. This is due to the high tooling costs and the maximum achievable pressures [174, 198]. In some highly stressed automotive parts which are produced in high volumes, PM can provide cost saving between 20 and 50% when compared to conventional forging or die casting processes by eliminating preassembly machining steps and reducing material losses [199].
The total cost of some manufacturing methods can vary tremendously according to the product size, material and manufacturing temperature. For example, centrifugal casting of Ti–ZrO2 of large FGM tubes that requires a high temperature resistant ceramic mould can shift the process fixed cost from a low cost to a high cost process [27].
Production volume is also decisive factor when considering economical aspects. For example, studies showed that AM can be more economically feasible for very small number of products as shown in Figs. 16 and 21. However, the smaller the product size and the material melting temperature, the more efficient and economical the process will be. For example, using smaller powder size and higher density as well as a smaller layer thickness and higher energy density in LENS process will cause a higher specific energy consumption and hence the total manufacturing costs. By controlling the processing condition, higher energy efficiency can be reached without affecting the product quality. For example, [23] give some recommendations for selecting laser power, scanning speeds, powder feed rates which are suitable for different materials (Inconel 718, Triboloy 800 and Stellite-1, AISI 4140) and comparing them to other materials available in literature.
For the purpose of classification, we assumed a medium sized product (in the mm-cm range) made of high melting point metallic material. Figure 22 represents a perspective for classification according to manufacturing costs, while Table 5 gives a range of capital cost for different FGM manufacturing equipment.
The classifications of available processing methods used to produce FG components are summarized in Table 6. Those classifications represent two groups of classifications. The first group is primarily dependent upon the physical characteristics of the FGMs and is obtained from literary information, while the second proposed group of classifications represents the proposed guidelines for designers and manufacturers.
5 FGMs challenges and new frontier
There are some issues that need further investigations and research efforts to make use of FGMs on industrial scale. The following points summarizes the main research directions that should be followed [123, 200]:
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1.
Building adequate material models that describe the physical properties of FGMs.
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2.
Developing a proper database for FGMs (including material systems, parameters, material preparation, performance evaluation and long-term reliability).
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3.
Improving the continuum theory, quantum (discrete) theory, percolation theory and micro-structure models.
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4.
Building computer simulation models for FGMs.
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5.
Investigating the performance of different FGMs in wear, fatigue, corrosion, residual stresses, semi-conductivity, etc. and optimizing the production parameters.
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6.
Developing a systematic methodology for selection of most adequate FGM production technique according to the required component’s characteristics.
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7.
Developing a systematic methodology for designing components made of FGMs according to the selected production technique.
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8.
Analyzing the economic aspects of the production processes aiming at integration into the mainstream of industry.
6 Summary and concluding remarks
Functionally graded materials have proven their position among modern advanced materials. They became a hard competitor in wide cluster of applications, especially in energy, defense, aviation and medicinal areas. The increasing interest of FGMs in research and industrial communities makes the introduction of several classifications with different points of view necessary. These allow more insight into the relationship among FGM properties, processing techniques, degree of control and cost.
This paper introduced a critical review of different classification methods used in the field of FGMs. These compared the advantages and limitations of the classified groups from different engineering points of view.
From designer and manufacturer point of view, new classifications of FGM production methods were proposed according to the complexity of product form and wall thickness, the realizable degree of control on properties gradient, the developed residual stresses due to the FGM production method, the equipment and manufacturing costs, the specific energy consumption and the environmental impact evaluated throughout the complete life cycle (Fig. 23). Some aspects were highlighted as challenges for FGMs on the industrial scale such as material modelling, numerical simulation, systematic selection and design methodologies as well as databank for FGMs. The adaptability for mass production, process repeatability, reliability and cost effectiveness are among the future frontier for FGMs.
References
Gupta B (2017) Few studies on biomedical applications of functionally graded material. Int J Eng Technol Sci Res IJETSR 4:39–43
Edwin A, Anand V, Prasanna K (2017) Sustainable development through functionally graded materials: an overview. Rasayan J Chem 10:149–152
Gupta A, Talha M (2015) Recent development in modeling and analysis of functionally graded materials and structures. Prog Aerosp Sci 79:1–14. https://doi.org/10.1016/j.paerosci.2015.07.001
Jha DK, Kant T, Singh RK (2013) A critical review of recent research on functionally graded plates. Compos Struct 96:833–849. https://doi.org/10.1016/j.compstruct.2012.09.001
Mahamood RM, Shukla M, Pityana S (2012) Functionally graded material: an overview. World Congr Eng III:2–6
Taguchi T, Tsubakiyama R, Miyajima K (2017) Yamamoto: effect of surface treatment on photoluminescence of silicon carbide nanotubes. Appl Surf Sci. https://doi.org/10.1016/j.apsusc.2017.01.176
Fakruddinali JY, Badarinarayan KS (2015) A survey on aluminum matrix composites. Ind J Sci Res Technol 3:34–42
Singh J, Chauhan A (2015) Characterization of hybrid aluminum matrix composites for advanced applications—a review. Int J Mater Res Technol. https://doi.org/10.1016/j.jmrt.2015.05.004
Bohidar SK, Sharma R, Mishra PR (2014) Functionally graded materials: a critical review. Int J Sci Footpr 2:18–29
Bakar W, Basri S, Jamaludin SN, Sajjad A (2018) Functionally graded materials: an overview of dental applications. World J Dent 9:137–144
Sato M, Inoue A, Shima H (2017) Bamboo-inspired optimal design for functionally graded hollow cylinders. PLoS ONE 12:1–14. https://doi.org/10.1371/journal.pone.0175029
Kokanee AA (2017) Review on functionally graded materials and various theories. Int Res J Eng Technol 4:890–893
Maimunnisa S, Gore P, Rajan TPD, Raja VS (2018) Role of centrifugal casting on electrochemical corrosion behavior of A356-SiCp composite in 3.5 wt% NaCl. J Mater Eng Perform. https://doi.org/10.1007/s11665-018-3508-2
Petit C, Montanaro L, Palmero P (2018) Functionally graded ceramics for biomedical application: concept, manufacturing, and properties. Int J Appl Ceram Technol. https://doi.org/10.1111/ijac.12878
Saleh B, Jiang J, Ma A, Song D, Yang D (2019) Effect of main parameters on the mechanical and wear behaviour of functionally graded materials by centrifugal casting: a review. Met Mater Int. https://doi.org/10.1007/s12540-019-00273-8
Udupa G, Rao SS, Gangadharan KV (2014) Functionally graded composite materials: an overview. Procedia Mater Sci 5:1291–1299. https://doi.org/10.1016/j.mspro.2014.07.442
Almasi D, Sadeghi M, Jye W, Roozbahani F, Iqbal N (2016) Functionally graded polymeric materials: a brif review of current fabrication methods and introduction of a novel fabrication method. Mater Sci Eng C 64:102–107. https://doi.org/10.1016/j.msec.2016.03.053
Singh AK (2018) A novel technique for manufacturing polypropylene based functionally graded materials. Int Polym Process 33:197–205
Jamaludin SNS, Mustapha F, Nuruzzman DM, Basri SN (2013) A review on the fabrication techniques of functionally graded ceramic–metallic materials in advanced composites. Sci Res Essays 8:828–840. https://doi.org/10.5897/SRE2012.0743
Saleh B, Jiang J, Ma A, Song D, Yang D, XU Q (2019) A Review on the influence of different reinforcements on the microstructure and wear behavior of functionally graded aluminum matrix composites by centrifugal casting. Met Mater Int. https://doi.org/10.1007/s12540-019-00491-0
Parihar RS, Setti SG, Sahu RK (2016) Recent advances in the manufacturing processes of functionally graded materials: a review. Sci Eng Compos Mater. https://doi.org/10.1515/secm-2015-0395
Bohidar SK, Sharma R, Mishra PR (2014) Functionally graded materials: a critical review. Int J Res 1:289–301
Liu ZY, Li C, Fang XY, Guo YB (2018) Energy consumption in additive manufacturing of metal parts. Procedia Manuf 26:834–845. https://doi.org/10.1016/j.promfg.2018.07.104
Akinlabi R, Mahamood E (2017) Functionally graded materials. Springer, Cham
Tan C, Wang C, Wang S, Wang G, Ji L, Tong Y, Duan X (2017) Investigation on 316L/316L-50 W/W plate functionally graded materials fabricated by spark plasma sintering. Fusion Eng Des. https://doi.org/10.1016/j.fusengdes.2017.08.001
Mahamood RM, Akinlabi ET (2015) Effect of laser power and powder flow rate on the wear resistance behaviour of laser metal deposited TiC/Ti6Al4V composites. Mater Today Proc 2:2679–2686. https://doi.org/10.1016/j.matpr.2015.07.233
Watanabe Y, Sato H (2011) Review Fabrication of Functionally Graded Materials under a Centrifugal Force. In: Cuppoletti J (ed) Nanocomposites with unique properties and applications in medicine and industry, Chap 7. InTech, Rijeka, Shanghai and New York, pp 133–150
Miyamoto Y (1999) Functionally graded materials: design, processing and applications. Kluwer Academic, Dordrecht
Miyamoto Y (1996) The applications of functionally graded materials in Japan. Mater Technol 11:230–236. https://doi.org/10.1080/10667857.1996.11752708
Sobczak J, Drenchev L (2009) Metal based functionally graded materials engineering and modeling. Bentham Science Publishers Ltd., Sharjah
Gasik M (2010) Functionally graded materials: bulk processing techniques. Int J Mater Prod Technol 39:20–29. https://doi.org/10.1504/IJMPT.2010.034257
Kieback B, Neubrand A, Riedel H (2003) Processing techniques for functionally graded materials. Mater Sci Eng A 362:81–105. https://doi.org/10.1016/S0921-5093(03)00578-1
Jayakumar E, Praveen AP, Rajan TPD, Pai BC (2018) Studies on tribological characteristics of centrifugally cast SiCp-reinforced functionally graded A319 aluminium matrix composites. Trans Indian Inst Met. https://doi.org/10.1007/s12666-018-1442-5
EL-Galy IM, Bassiouny BI, Ahmed MH (2018) Empirical model for dry sliding wear behavior of centrifugally cast functionally graded composite based on pure Al/SiCp. Key Eng Mater 786:276–285. https://doi.org/10.4028/www.scientific.net/KEM.786.276
Guo-qin C, Zi-yang X, Song-he M, Gao-hui W, De-zhi Z (2009) Thermal expansion and mechanical properties of high reinforcement content SiCp/Cu composites fabricated by squeeze casting technology. Trans Nonferrous Met Soc China 19:s600–s604. https://doi.org/10.1016/S1003-6326(10)60116-1
Pai BC, Rajan TPD (2009) Development in manufacturing processes of functionally graded materials. IJAEA 2:64–74
Yuan L, Ding S, Wen C (2019) Additive manufacturing technology for porous metal implant applications and triple minimal surface structures: A review. Bioact Mater 4(1): 56–70. https://doi.org/10.1016/j.bioactmat.2018.12.003
Watanabe Y, Miura-Fujiwara E, Sato H (2010) Fabrication of functionally graded materials by centrifugal slurry pouring method and centrifugal mixed powder method. J Jpn Soc Powder Powder Metall 57:321–326
Watanabe Y, Miura-Fujiwara E, Sato H (2011) Fabrication of functionally graded materials by combination of centrifugal force and sintering method. J Jpn Soc Powder Powder Metall 58:11–17
Tripathy A, Sarangi SK, Chaubey A (2018) A review of solid state processes in manufacture of functionally graded materials. Int J Eng Technol 7:1–5. https://doi.org/10.14419/ijet.v7i4.39.23686
Popoola P, Farotade G, Fatoba G, Popoola O (2016) Laser engineering net shaping method in the area of development of functionally graded materials (FGMs) for aero engine applications. In: Paul MC (ed) A Review, from "Fiber Laser", Chap 17, pp 383–400. ISBN: 978-953-51-2257-9
Malandrino G (2009) Chemical vapour deposition. In: Jones C, Hitchman M (eds) Precursors, processes and applications. Angewandte Chemie International Edition, 48, pp 7478–7479
Ansari A, Alhoshan M, Alsalhi M, Aldwayyan A (2010) Prospects of nanotechnology in clinical immunodiagnostics. Sensors 10:6535–6581. https://doi.org/10.3390/s100706535
Seol Y, Kang T, Cho D (2012) Solid freeform fabrication technology applied to tissue engineering with various biomaterials. Soft Matter View 8:1730–1735. https://doi.org/10.1039/c1sm06863f
Chen F, Zhang C, Chen F, Huang Z, Jia M, Chen G, Ye Y, Lin Y, Liu W, Chen B, Shen Q, Zhang L, Lavernia EJ (2019) Additive manufacturing of functionally graded materials: a review. Mater Sci Eng A 764:138209. https://doi.org/10.1016/j.msea.2019.138209
Leu MC, Deuser BK, Tang L, Landers RG, Hilmas GE, Watts JL (2012) Freeze-form extrusion fabrication of functionally graded materials. CIRP Ann Manuf Technol 61:223–226. https://doi.org/10.1016/j.cirp.2012.03.050
Kumar R, Chandrappa C (2014) Synthesis and characterization of Al–SiC functionally graded material composites using powder metallurgy techniques. Int J Innov Res Sci Eng Technol 3:15464–15471. https://doi.org/10.15680/IJIRSET.2014.0308054
Watanabe Y, Inaguma O, Sato H, Miura-Fujiwara E (2009) A novel fabrication method for functionally graded materials under centrifugal force: the centrifugal mixed-powder method. Materials (Basel) 2:2510–2525. https://doi.org/10.3390/ma2042510
Naebe M, Shirvanimoghaddam K (2016) Functionally graded materials: a review of fabrication and properties. Appl Mater Today 5:223–245. https://doi.org/10.1016/j.apmt.2016.10.001
Cirakoglu M, Bhaduri S, Bhaduri SB (2002) Combustion synthesis processing of functionally graded materials in the Ti-B binary system. J Alloys Compd 347:259–265
Bhattacharyya M, Nath A, Kapuria S (2007) Synthesis and characterization of Al/SiC and Ni/Al2O3 functionally graded materials. Mater Sci Eng A 487:524–535. https://doi.org/10.1016/j.msea.2007.10.040
Canakci A, Varol T, Özkaya S, Erdemir F (2014) Microstructure and properties of Al–B4C functionally graded materials produced by powder metallurgy method. Univers J Mater Sci 2:90–95. https://doi.org/10.13189/ujms.2014.020502
Arenas A, Rocha LA, Velhinho A (2014) Anodization mechanism on SiC nanoparticle reinforced Al matrix composites produced by power metallurgy. Materials (Basel) 7:8151–8167. https://doi.org/10.3390/ma7128151
Erdemir F, Canakci A, Varol T (2015) Microstructural characterization and mechanical properties of functionally graded Al2024/SiC composites prepared by powder metallurgy techniques. Trans Nonferrous Met Soc 25:3569–3577. https://doi.org/10.1016/S1003-6326(15)63996-6
Strojny A et al (2016) The influence of Al2O3 powder morphology on the properties of Cu–Al2O3 composites designed for functionally graded materials (FGM). J Mater Eng Perform 25:3173–3184. https://doi.org/10.1007/s11665-016-2204-3
Sanuddin AB, Aidy A (2012) Fabrication of Al/Al2O3 FGM rotating disc. Int J Automot Mech Eng 5:622–629
Watanabe Y et al (2010) Fabrication of Al–Al3Ti/Ti3Al functionally graded materials under a centrifugal force. Materials (Basel) 3:4639–4656. https://doi.org/10.3390/ma3094639
Kelestemur MH (2002) Processing and microstructural characterization of functionally gradient Al A359/SiCp composite. J Mater Sci 7:1813–1821
Velhinho A, Botas JD, Ariza E, Gomes JR, Rocha LA (2004) Tribocorrosion studies in centrifugally cast Al-matrix SiCp-reinforced functionally graded composites. Mater Sci Forum 456:871–875
Rajan TPD, Pillai RM, Pai BC (2008) Centrifugal casting of functionally graded aluminium matrix composite components. Int J Cast Met Res. https://doi.org/10.1179/136404608x361972
Vieira AC, Sequeira PD, Gomes JR, Rocha LA (2009) Dry sliding wear of Al alloy/SiCp functionally graded composites: influence of processing conditions. Wear 267:585–592. https://doi.org/10.1016/j.wear.2009.01.041
Rajan TPD, Pai BC (2009) Formation of solidification microstructures in centrifugal cast functionally graded aluminium composites. Trans Indian Inst Met 62:383–389
Rajan TPD, Pillai RM, Pai BC (2010) Characterization of centrifugal cast functionally graded aluminum–silicon carbide metal matrix composites. Mater Charact 61:923–928. https://doi.org/10.1016/j.matchar.2010.06.002
Velhinho A (2010) Corrosion behaviour of aluminium syntactic functionally graded composites. Int J Mater Prod Technol. https://doi.org/10.1504/IJMPT.2010.034265
Rajan TPD, Pai BC (2011) Processing of functionally graded aluminium matrix composites by centrifugal casting technique. Mater Sci Forum 690:157–161. https://doi.org/10.4028/www.scientific.net/MSF.690.157
Kai W, Wenju S (2011) Microstructures in centrifugal casting of SiCp/AlSi9Mg composites with different mould rotation speeds. J Wuhan Univ Technol Sci Ed 26:504–509. https://doi.org/10.1007/s11595-011-0257-6
Prasad T (2011) Experimental investigation on the effect of particle loading on microstructural, mechanical and fractural properties of Al/Al2O3 functionally graded materials. Int J Adv Eng Technol II:161–166
Mohammadi M et al (2014) Characterization of the graded distribution of primary particles and wear behavior in the A390 alloy ring with various Mg contents fabricated by centrifugal casting. J Mater 56:105–114. https://doi.org/10.1016/j.matdes.2013.10.070
Wang K (2012) An approach for increase of reinforcement content in particle rich zone of centrifugally cast SiCP/Al composites. J Compos Mater. https://doi.org/10.1177/0021998311414070
Savaş Ö (2013) Production of functionally graded AlB2/Al–4%Mg composite by centrifugal casting. Period Eng Nat Sci 1:2–7. https://doi.org/10.21533/pen.v1i2.23
Ramakrishna S, Manjunath U, Jayakumar E, Rajan TPD, Pai BC, Nagaraja (2014) Processing and characterization of SiCp reinforced functionally graded AA 6061 aluminium metal matrix composites. Adv Mech Robot Eng 1:61–65
Varol F (2014) Production of functionally graded SiC/Al–Cu–Mg composite by centrifugal casting. Sci Eng Compos Mater. https://doi.org/10.1515/secm-2014-0141
Babu KV, Jappes JTW, Rajan TPD (2014) Dry sliding wear studies on SiC reinforced functionally graded aluminium matrix composites. J Mater Des Appl 230:182–189. https://doi.org/10.1177/1464420714556665
Radhika N, Raghu R (2015) Mechanical and tribological properties of functionally graded aluminium/zirconia metal matrix composite synthesized by centrifugal casting. Int J Mater Res 106:1–8
Karun AS, Rajan TPD, Pillai UTS, Pai BC, Rajeev VR (2016) Enhancement in tribological behaviour of functionally graded SiC reinforced aluminium composites by centrifugal casting. J Compos Mater 50:2255–2269. https://doi.org/10.1177/0021998315602946
Jayakumar E, Jacob JC, Rajan TPD, Joseph MA, Pai BC (2015) Processing and characterization of hypoeutectic functionally graded aluminum–SiC metal matrix composites. Mater Sci Forum 831:456–459. https://doi.org/10.4028/www.scientific.net/MSF.830-831.456
Wang K, Zhili H (2016) Mechanical and thermal expansion properties of SiCp/ZAlSi9Mg composites produced by centrifugal casting. J Wuhan Univ Technol Sci Ed. https://doi.org/10.1007/s11595-016-1352-5
Radhika N, Raghu R (2016) Development of functionally graded aluminium composites using centrifugal casting and influence of reinforcements on mechanical and wear properties. Trans Nonferrous Met Soc 26:905–916. https://doi.org/10.1016/S1003-6326(16)64185-7
Watanabe Y, Sato H, Ogawa T, Kim I (2007) Density and hardness gradients of functionally graded material ring fabricated from Al-3 mass% Cu alloy by a centrifugal in-situ method. Mater Trans 48:2945–2952. https://doi.org/10.2320/matertrans.MB200710
Ulukoy A, Topcu M, Tasgetiren S (2016) Experimental investigation of aluminum matrix functionally graded material: microstructural and hardness analyses, fretting, fatigue, and mechanical properties. Proc Inst Mech Eng Part J J Eng Tribol 230:143–155. https://doi.org/10.1177/1350650115594405
Radhika N (2016) Analysis of tribological behaviour of functionally graded LM13 aluminium/TiS2 composite using design of experiments. Tribol Ind 38:425–434
Jayakumar E, Jacob JC, Rajan TPD, Joseph MA, Pai BC (2016) Processing and characterization of functionally graded aluminum (A319)-SiCp metallic composites by centrifugal casting technique. Metall Mater Trans A 47:4306–4315. https://doi.org/10.1007/s11661-016-3558-8
Radhika N (2016) Mechanical properties and abrasive wear behaviour of functionally graded Al-Si12Cu/Al2O3 metal matrix composite. Trans Indian Inst Met 70:145–157. https://doi.org/10.1007/s12666-016-0870-3
Junus S, Zulfia A (2016) Development of seamless pipe based on Al/Al2O3 composite produced by stir casting and centrifugal casting. Mater Sci Forum 857:179–182. https://doi.org/10.4028/www.scientific.net/MSF.857.179
Prabhu TR (2016) Processing and properties evaluation of functionally continuous graded 7075 Al alloy/SiC composites. Arch Civ Mech Eng 17:20–31. https://doi.org/10.1016/j.acme.2016.08.004
Radhika N, Raghu R, Vidyapeetham AV (2017) Synthesis of functionally graded aluminium composite and investigation on its abrasion wear behaviour. J Eng Sci Technol 12:1386–1398
Mohandas A, Radhika N (2017) Studies on mechanical behaviour of aluminium/nickel coated silicon carbide reinforced functionally graded composite. Tribol Ind 39:145–151. https://doi.org/10.24874/ti.2017.39.02.01
El-Galy IM, Ahmed MH, Bassiouny BI (2017) Characterization of functionally graded Al-SiCp metal matrix composites manufactured by centrifugal casting. Alex Eng J. https://doi.org/10.1016/j.aej.2017.03.009
Radhika N, Raghu R (2017) Characterization of mechanical properties and three-body abrasive wear of functionally graded aluminum LM25/titanium carbide metal matrix composite. Mat-wiss u Werkstofftech 48:882–892. https://doi.org/10.1002/mawe.201700559
Song NN et al (2011) Hydraulic experiments of mold filling process in horizontal centrifugal casting. Adv Mater Res. https://doi.org/10.4028/www.scientific.net/AMR.154-155.314
Sam M, Radhika N (2017) Development of functionally graded Cu–Sn–Ni/Al2O3 composite for bearing applications and investigaton of its mechanical and wear behaviour. Part Sci Technol. https://doi.org/10.1080/02726351.2017.1364312
Muddamsetty L, Radhika N (2016) Effect of heat treatment on the wear behaviour of functionally graded LM13/B4C composite. Tribol Ind 38:108–114
Narendranath S, Kumar GCM (2013) Properties of centrifugal casting at different rotational speeds of the die. Int J Emerg Technol Adv Eng 3:727–731
Chirita G, Soares D, Silva FS (2008) Advantages of the centrifugal casting technique for the production of structural components with Al–Si alloys. Mater Des 29:20–27. https://doi.org/10.1016/j.matdes.2006.12.011
Melgarejo ZH, Suárez OM, Sridharan K (2008) A microstructure and properties of functionally graded Al–Mg–B composites fabricated by centrifugal casting. Compos Part A 39:1150–1158. https://doi.org/10.1016/j.compositesa.2008.04.002
El-hadad S, Sato H, Watanabe Y (2010) Wear of Al/Al3Zr functionally graded materials fabricated by centrifugal solid-particle method. J Mater Process Technol 210:2245–2251. https://doi.org/10.1016/j.jmatprotec.2010.08.012
Qin XH, Han WX, Fan CG (2002) Research on distribution of SiC particles in aluminum-alloy matrix functionally graded composite tube manufactured by centrifugal casting. J Mater Sci Lett 21:665–667
Jamian S, Razali SNF, Abidin MRZ (2016) FGNF/epoxy composite fabricated using centrifugal slurry-pouring method. J Eng Appl Sci 11:7759–7764
Kinoshita K, Sato H, Watanabe Y (2010) Development of compositional gradient simulation for centrifugal slurry-pouring methods. Mater Sci Forum 631–632:455–460. https://doi.org/10.4028/www.scientific.net/MSF.631-632.455
Inaguma Y, Sato H, Watanabe Y (2009) Fabrication of Al-based FGM containing TiO nano-particles by a centrifugal mixed-powder method. Mater Sci Forum 631–632:441–447. https://doi.org/10.4028/www.scientific.net/MSF.631-632.441
Jayachandran M, Tsukamoto H, Sato H, Watanabe Y (2013) Formation behavior of continuous graded composition in Ti–ZrO2 functionally graded materials fabricated by mixed-powder pouring method. J Nanomater. https://doi.org/10.1155/2013/504631
Watanabe Y, Shibuya M, Sato H (2013) Fabrication of Al/diamond particles functionally graded materials by centrifugal sintered-casting method. J Phys Conf Ser. https://doi.org/10.1088/1742-6596/419/1/012002
Herzog D, Seyda V, Wycisk E, Emmelmann C (2016) Additive manufacturing of metals. Acta Mater 117:371–392. https://doi.org/10.1016/j.actamat.2016.07.019
Bodaghi M, Damanpack AR, Liao WH (2017) Adaptive metamaterials by functionally graded 4D printing. Mater Des 135:26–36. https://doi.org/10.1016/j.matdes.2017.08.069
Hutmacher DW, Sittinger M, Risbud MV (2004) Scaffold-based tissue engineering: Rationale for computer-aided design and solid free-form fabrication systems. Trends Biotechnol 22:354–362. https://doi.org/10.1016/j.tibtech.2004.05.005
Su B et al (2010) Study on the preparation of the SiCp/Al–20Si–3Cu functionally graded material using spray deposition. Mater Sci Eng A 527:6660–6665. https://doi.org/10.1016/j.msea.2010.06.090
Gu YW, Khor KA, Fu YQ, Wang Y (1997) Functionally graded ZrO2-NiCrAlY coatings prepared by plasma spraying using pre-mixed, spheroidized powders. Surf Coat Technol 96(2–3):305–312. https://doi.org/10.1016/s0257-8972(97)00185-0
Sampath S, Herman H, Shimoda N, Saito T (1995) Thermal spray processing of FGMs. MRS Bull 20:27–31. https://doi.org/10.1557/S0883769400048880
Askari E et al (2012) Fabrication and mechanical properties of Al2O3/SiC/ZrO2 functionally graded material by electrophoretic deposition. J Mech Behav Biomed Mater 12:144–150. https://doi.org/10.1016/j.jmbbm.2012.02.029
Lajevardi SA, Shahrabi T, Szpunar JA (2013) Synthesis of functionally graded nano Al2O3–Ni composite coating by pulse electrodeposition. Appl Surf Sci 279:180–188. https://doi.org/10.1016/j.apsusc.2013.04.067
Allahyarzadeh MH, Aliofkhazraei M, Rouhaghdam ARS, Torabinejad V (2016) Functionally graded nickel–tungsten coating: electrodeposition, corrosion and wear behaviour. Can Metall Q 55:303–311. https://doi.org/10.1080/00084433.2016.1190542
Bhavar V et al (2017) A review on function-ally gradient materials (FGMs) and their applications. IOP Conf Ser Mater Sci Eng. https://doi.org/10.1088/1757-899X/229/1/012021
Joshi A, Patnaik A, Gangil B, Kumar S (2012) Laser assisted rapid manufacturing technique for the manufacturing of functionally graded materials. In: Conference on engineering and systems, pp 1–3
Li W, Zhang J, Zhang X, Liou F (2017) Effect of optimizing particle size on directed energy deposition of functionally graded material with blown pre-mixed multi-powder. Manuf Lett 13:39–43. https://doi.org/10.1016/j.mfglet.2017.07.001
Yin GF et al (1999) Preparation of DLC gradient biomaterials by means of plasma source ion implant-ion beam enhanced deposition. Thin Solid Films 345:67–70. https://doi.org/10.1016/S0040-6090(99)00076-0
Lim YM, Park YJ, Yun YH, Hwang KS (2002) Functionally graded Ti/HAP coatings on Ti–6Al–4V obtained by chemical solution deposition. Ceram Int 28:37–41. https://doi.org/10.1016/S0272-8842(01)00055-4
Zahedi AM et al (2009) Processing and impact behavior of Al/SiCp composites fabricated by the pressureless melt infiltration method. Ceram Int 35:1919–1926. https://doi.org/10.1016/j.ceramint.2008.10.024
Jedamzik R (2000) Functionally graded materials by electrochemical processing and infiltration: application to tungsten/copper composites. J Mater Sci 5:477–486
Hassanin H, Jiang K (2010) Infiltration-processed, functionally graded materials for microceramic componenets. In: Proceedings of the IEEE international conference on micro electro mechanical systems (MEMS), pp 368–371
Manu KMS, Resmi VG, Brahmakumar M, Narayanasamy P, Rajan TPD, Pavithran C, Pai BC (2012) Squeeze infiltration processing of functionally graded aluminum–SiC metal ceramic composites. Trans Indian Inst Met 65:747–751. https://doi.org/10.1007/s12666-012-0170-5
Makwana A, Panchal KC (2014) Stress analysis of functionally graded material plate with cut-out. Int J Eng Res Technol 3:2020–2025
Ramesh MR, Aithal K (2019) Evaluation of mechanical and tribological properties of directionally solidified Al–Si based FG composite. Silicon. https://doi.org/10.1007/s12633-019-00179-5
Khan S (2015) Analysis of tribological applications of functionally graded materials in mobility engineering. Int J Sci Eng Res 6:1150–1160
Radhika N, Raghu R (2014) Three body abrasion wear behaviour of functionally graded aluminium/B4C metal matrix composite using design of experiments. Procedia Eng 97:713–722. https://doi.org/10.1016/j.proeng.2014.12.301
Mahmoud D, Elbestawi M (2017) Lattice structures and functionally graded materials applications in additive manufacturing of orthopedic implants: a review. J Manuf Mater Process 1:13. https://doi.org/10.3390/jmmp1020013
Popovich VA, Borisov EV, Popovich AA, Sufiiarov VS, Masaylo DV, Alzina L (2016) Functionally graded Inconel 718 processed by additive manufacturing: crystallographic texture, anisotropy of microstructure and mechanical properties. JMADE 114:441–449. https://doi.org/10.1016/j.matdes.2016.10.075
Zhang X, Fang G, Leeflang S, Zadpoor AA, Zhou J (2018) Topological design, permeability and mechanical behavior of additively manufactured functionally graded porous metallic biomaterials. Acta Biomater. https://doi.org/10.1016/j.actbio.2018.12.013
Mota AF, Loja MAR (2019) Mechanical behavior of porous functionally graded nanocomposite materials. J Carbon Res 5:34
Gabbrielli R, Turner IG, Bowen CR (2008) Development of modelling methods for materials to be used as bone substitutes. Key Eng Mater 363:903–906. https://doi.org/10.4028/www.scientific.net/KEM.361-363.903
Muller P, Mognol P, Hascoet JY (2013) Modeling and control of a direct laser powder deposition process for Functionally graded materials (FGM) parts manufacturing. J Mater Process Technol 213:685–692. https://doi.org/10.1016/j.jmatprotec.2012.11.020
Song J et al (2013) Preparation of W–Cu functionally graded material coated with CVD–W for plasma-facing components. J Nucl Mater 442:S208–S213. https://doi.org/10.1016/j.jnucmat.2013.01.326
Rodriguez J, Hoefer K, Haelsig A, Mayr P (2019) Functionally graded SS 316L to Ni-based structures produced by 3D plasma metal deposition. Metals (Basel) 9:620
Pei Y, De Hosson JT (2000) Functionally graded materials produced by laser cladding. Acta Mater 48:2617–2624. https://doi.org/10.1016/S1359-6454(00)00065-3
del Val J, Arias-González F, Barro O, Riveiro A, Comesaña R, Penide J, Lusquiños F, Bountinguiza M, Quintero F, Pou J (2017) Functionally graded 3D structures produced by laser cladding. Procedia Manuf 13:169–176. https://doi.org/10.1016/j.promfg.2017.09.029
Yin S, Yan X, Chen C, Jenkins R, Liu M, Lupoi R (2018) Hybrid additive manufacturing of Al–Ti6Al4V functionally graded materials with selective laser melting and cold spraying. J Mater Process Technol. https://doi.org/10.1016/j.jmatprotec.2018.01.015
Parihar RS, Setti SG, Sahu RK (2017) Preliminary investigation on development of functionally graded cemented tungsten carbide with solid lubricant via ball milling and spark plasma sintering. J Compos Mater. https://doi.org/10.1177/0021998317724217
Tripathy A, Sarangi SK, Panda R (2017) Fabrication of functionally graded composite material using powder metallurgy route: an overview. Int J Mech Prod Eng Res Dev 7:135–146
Sobczak JJ, Drenchev L (2013) Metallic functionally graded materials: a specific class of advanced composites. J Mater Sci Technol. https://doi.org/10.1016/j.jmst.2013.02.006
Saleh BI, Ahmed MH (2019) Development of functionally graded tubes based on pure Al/Al2O3 metal matrix composites manufactured by centrifugal casting for automotive applications. Met Mater Int. https://doi.org/10.1007/s12540-019-00391-3
Zhang B, Jaiswal P, Rai R, Nelaturi S (2016) Additive manufacturing of functionally graded objects: a review. In: Proceedings of the ASME international design engineering technical conferences and computers and information in engineering conference, pp 1–17
Jia Q, Gu D (2014) Selective laser melting additive manufacturing of Inconel 718 superalloy parts: densification, microstructure and properties. J Alloys Compd 585:713–721. https://doi.org/10.1016/j.jallcom.2013.09.171
Alimardani M, Paul C P, Toyserkani E, Khajepour A (2010) Multiphysics modelling of laser solid freeform fabrication techniques. Adv Laser Mater Process. https://doi.org/10.1533/9781845699819.8.765
El-Desouky A, Kassegne SK, Moon KS, McKittrick J, Morsi K (2013) Rapid processing and characterization of micro-scale functionally graded porous materials. J Mater Process Technol 213:1251–1257. https://doi.org/10.1016/j.jmatprotec.2013.01.019
Erdemir F, Canakci A, Varol T (2015) Microstructural characterization and mechanical properties of functionally graded Al2024/SiC composites prepared by powder metallurgy techniques. Trans Nonferrous Met Soc China 25:3569–3577. https://doi.org/10.1016/S1003-6326(15)63996-6
Siddhartha AP (2009) Functionally graded materials manufacturing techniques. Mater Sci 5:523–539
Ngo TD, Kashani A, Imbalzano G, Nguyen KTQ, Hui D (2018) Additive manufacturing (3D printing): A review of materials, methods, applications and challenges. Compos B Eng 143:172–196
Kaushal S, Gupta D, Bhowmick H (2017) An approach for functionally graded cladding of composite material on austenitic stainless steel substrate through microwave heating. J Compos Mater. https://doi.org/10.1177/0021998317705977
Wei C, Sun Z, Chen Q, Liu Z, Li L (2019) Additive manufacturing of horizontal and 3D functionally graded 316L/Cu10Sn components via multiple material selective laser melting. J Manuf Sci Eng 141:1–8. https://doi.org/10.1115/1.4043983
Niinomi M, Narushima T, Nakai M (2015) Advances in metallic biomaterials (processing and applications). Springer, Berlin
Chmielewski M, Pietrzak K (2016) Metal–ceramic functionally graded materials: manufacturing, characterization, application. Bull Polish Acad Sci Tech Sci 64:151–160. https://doi.org/10.1515/bpasts-2016-0017
Sai H (2018) A review on functionally gradient materials (FGMs) and their applications. Int J Curr Eng Technol 8:79–84
Udupa G, Shrikantha Rao S, Gangadharan KV (2012) Future applications of carbon nanotube reinforced functionally graded composite materials. In: IEEE international conference on advances in engineering, science and management (ICAESM), 2012, pp 399–404
Tharaknath S, Ramkumar R, Lokesh B (2016) Design and analysis of hip prosthesis using functionally graded material. Middle East J Sci Res 24:124–132. https://doi.org/10.5829/idosi.mejsr.2016.24.RIETMA120
Pompe W, Worch H, Epple M, Friess W, Gelinsky M, Greil P, Hempel U, Scharnweber D, Schulte K (2003) Functionally graded materials for biomedical applications. Mater Sci Eng A 362:40–60. https://doi.org/10.1016/S0921-5093(03)00580-X
Sola A, Bellucci D, Cannillo V (2015) Functionally graded materials for orthopedic applications: an update on design and manufacturing. Biotechnol Adv. https://doi.org/10.1016/j.biotechadv.2015.12.013
Bharti I, Gupta N, Gupta KM (2013) Novel applications of functionally graded nano, optoelectronic and thermoelectric materials. Int J Mater Mech Manuf 1:221–224. https://doi.org/10.7763/IJMMM.2013.V1.47
Suryanarayanan K, Praveen R, Raghuraman S (2013) Silicon carbide reinforced aluminium metal matrix composites for aerospace applications: a literature review. Int J Innov Res Sci Eng Technol 2:6336–6344
Cooley W (2005) Application of functionally graded materials in aircraft structures. Thesis, Department of the air force, Air University, USA. https://apps.dtic.mil/dtic/tr/fulltext/u2/a434403. Accessed 15 Sept 2019
Chakrabarty I (2017) High temperature tensile properties of centrifugally cast in situ Al–Mg2Si functionally graded composites for automotive cylinder block liners. J Alloys Compd 724:84–97. https://doi.org/10.1016/j.jallcom.2017.06.306
Li Y, Jian S, Min Z (2005) Application of ceramics metal functionally graded materials on green automobiles. Key Eng Mater 280–283:1925–1928. https://doi.org/10.4028/www.scientific.net/KEM.280-283.1925
Shahistha ACPM, Binol V, Anjali B (2014) A review on functionally graded materials. Int J Eng Sci 3:90–101
Chin ESC (1999) Army focused research team on functionally graded armor composites. Mater Sci Eng A 259:155–161. https://doi.org/10.1016/S0921-5093(98)00883-1
El-Wazery MS, El-Desouky AR (2015) A review on functionally graded ceramic–metal materials. J Mater Environ Sci 6:1369–1376
Niino M, Kisara K, Mori M (2005) Feasibility study of FGM technology in space solar power systems (SSPS). Mater Sci Forum 492–493:163–170. https://doi.org/10.4028/www.scientific.net/MSF.492-493.163
Shariat BS, Meng Q, Mahmud AS, Wu Z, Bakhtiari R, Zhang J, Motazedian F, Yang H, Rio G, Nam T, Liu Y (2017) Functionally graded shape memory alloys: design, fabrication and experimental evaluation. Mater Des 124:225–237. https://doi.org/10.1016/j.matdes.2017.03.069
Coomar N, Kadoli R (2010) Comparative analysis of steady state heat transfer in a TBC and functionally graded air cooled gas turbine blade. Indian Acad Sci 35:1–17. https://doi.org/10.1007/s12046-010-0006-0
Tarlochan F (2012) Functionally graded material: a new breed of engineered material. J Appl Mech Eng 02:10–11. https://doi.org/10.4172/2168-9873.1000e115
Stoner B, Bartolai J, Kaweesa DV, Meisel NA, Simpson TW (2018) Achieving functionally graded material composition through bicontinuous mesostructural geometry in material extrusion additive manufacturing. JOM 70:413–418. https://doi.org/10.1007/s11837-017-2669-z
Oshkour AA, Talebi H, Farid S, Shirazi S, Yau YH, Tarlochan F, Azuan N, Osman A (2014) Effect of geometrical parameters on the performance of longitudinal functionally graded femoral prostheses. Int Cent Artif Organs Transplant Wiley Period. https://doi.org/10.1111/aor.12315
Chiu WK, Yu KM (2008) digital manufacturing of three-dimensional functionally graded material objects. Comput Des 40:1080–1093. https://doi.org/10.1016/j.cad.2008.10.002
Asemi K, Salehi M, Akhlaghi M (2013) Three dimensional static analysis of two dimensional functionally graded plates. Int J Recent Adv Mech Eng 2:21–32
Li Q, Iu VPÃ, Kou KP (2009) Three-dimensional vibration analysis of functionally graded material plates in thermal environment. J Sound Vib 324:733–750. https://doi.org/10.1016/j.jsv.2009.02.036
Lindahl J (2016) Characterizing material transition for functionally graded material using big area additive manufacturing. In: Proceedings of the 26th annual international solid freeform fabrication symposium—an additive manufacturing conference, pp 738–747
Chang I, Zhao Y (eds) (2013) Advances in powder metallurgy: properties, processing and applications. In: A volume in woodhead publishing series in metals and surface engineering. Elsevier, London
Wetherhold RC, Seelman S, Wang J (1996) The use of functionally graded materials to eliminate or control thermal deformation. Compos Sci Technol 56(9):1099–1104
Zhu D, Chen J (2014) Thermal stress analysis on chemical vapor deposition tungsten coating as plasma facing material for EAST. J Nucl Mater 455:185–188. https://doi.org/10.1016/j.jnucmat.2014.05.054
Mehrali M, Wakily H, Metselaar IHSC (2011) Residual stress and mechanical properties of Al2O3/ZrO2 functionally graded material prepared by EPD from 2-butanone based suspension. Adv Appl Ceram 110:35–40. https://doi.org/10.1179/174367610X12804792635143
Shah K, Haq IU, Shah SA, Khan FU, Khan MT, Khan S (2014) Experimental study of direct laser deposition of Ti–6Al–4V and inconel 718 by using pulsed parameters. Sci World J. https://doi.org/10.1155/2014/841549
Pei Y, Ocelı́k V, De Hosson JT (2003) Interfacial adhesion of laser clad functionally graded materials. Mater Sci Eng A 342:192–200. https://doi.org/10.1016/s0921-5093(02)00249-6
Matějíček J, Mušálek R, Chráska P (2014) Residual stresses and Young’s moduli of plasma sprayed W + Cu composites and FGMs determined by in situ curvature method. Key Eng Mater 606:151–154. https://doi.org/10.4028/www.scientific.net/KEM.606.151
Watanabe Y, Fukui Y (1996) Analysis of thermal residual stress in a thick-walled ring of duralcan-base Al–SiC functionally graded material. Metall Mater Trans A 27:4145–4151. https://doi.org/10.1007/BF02595662
Xu C, Todd RI (2015) Functionally graded ceramics by a new in situ processing route: residual stress and wear resistance. J Eur Ceram Soc 35:2693–2698. https://doi.org/10.1016/j.jeurceramsoc.2015.02.032
Dancer CEJ, Achintha M, Salter CJ, Fernie JA, Todd RI (2012) Residual stress distribution in a functionally graded alumina–silicon carbide material. Scr Mater 67:281–284. https://doi.org/10.1016/j.scriptamat.2012.05.002
Jung Y-G, Choi S-C, Oh C-S, Paik U-G (1997) Residual stress and thermal properties of zirconia/metal (nickel, stainless steel 304) functionally graded materials fabricated by hot pressing. J Mater Sci 32:3841–3850. https://doi.org/10.1023/A:1018640126751
Ekbote B, Patrick K (2006) Micromechanics-based design and processing of efficient meso-scale heat exchanger. Los Alamos Natl Lab 836:1–15
Muliana A (2012) The effects of residual stresses and degradation on the response of viscoplastic functionally graded materials. Compos Struct 94:3354–3363. https://doi.org/10.1016/j.compstruct.2012.04.016
Liu W, Wei H (2019) Energy efficiency evaluation of metal laser direct deposition based on process characteristics and empirical modeling. Int J Adv Manuf Technol 102:901–913
Liu Z, Ning F, Cong W, Jiang Q, Li T, Zhang H (2016) Energy consumption and saving analysis for laser engineered net shaping of metal powders. Energ Artic 9:1–12. https://doi.org/10.3390/en9100763
Salonitis K, Jolly MR, Zeng B, Mehrabi H (2016) Improvements in energy consumption and environmental impact by novel single shot melting process for casting. J Clean Prod 137:1532–1542. https://doi.org/10.1016/j.jclepro.2016.06.165
Previtali B, Demir AG, Bucconi M, Crosato A, Penasa M (2017) Comparative costs of additive manufacturing vs. machining: the case study of the production of forming dies for tube bending. In: Solid freeform fabrication 2017: proceedings of the 28th annual international solid freeform fabrication symposium—an additive manufacturing conference, pp 2816–2834
Yoon H, Lee J, Kim H, Kim M, Kim E, Shin Y (2014) A comparison of energy consumption in bulk forming, subtractive, and additive processes: review and case study. Int J Precis Eng Manuf Green Technol 1:261–279. https://doi.org/10.1007/s40684-014-0033-0
Azevedo JMC, Serrenho AC, Allwood JM (2018) Energy and material efficiency of steel powder metallurgy. Powder Technol. https://doi.org/10.1016/j.powtec.2018.01.009
Ingarao G, Priarone PC, Deng Y, Paraskevas D (2018) Environmental modelling of aluminium based components manufacturing routes: additive manufacturing versus machining versus forming. J Clean Prod 176:261–275. https://doi.org/10.1016/j.jclepro.2017.12.115
Liu Z, Jiang Q, Ning F, Kim H, Cong W, Xu C, Zhang H (2018) Investigation of energy requirements and environmental performance for additive manufacturing processes. Sustainability 10:2–15. https://doi.org/10.3390/su10103606
Reinhold E, Richter J, Seyfert U, Steuer C (2004) Metal strip coating by electron beam PVD—industrial requirements and customized solutions. Surf Coat Technol 189:708–713. https://doi.org/10.1016/j.surfcoat.2004.07.007
Stief P, Dantan J, Etienne A, Siadat A (2019) Energy effectiveness effectiveness in additive additive manufacturing using design for for property. Procedia CIRP 80:132–137. https://doi.org/10.1016/j.procir.2019.01.082
Douglas S, Stanley W (2015) Costs and cost effectiveness of additive manufacturing a literature review and discussion. NIST Spec Publ. https://doi.org/10.6028/NIST.SP.1176
Qian M, Froes FHS (2015) Titanium powder metallurgy science, technology and applications. Elsevier, New York
James WB (2015) Powder metallurgy methods and applications. In: Powder metallurgy, pp 4–11
Tejaswini N, Babu R, Ram S (2013) Functionally graded material: an overview. Int J Adv Eng Sci Technol 4:183–188
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El-Galy, I.M., Saleh, B.I. & Ahmed, M.H. Functionally graded materials classifications and development trends from industrial point of view. SN Appl. Sci. 1, 1378 (2019). https://doi.org/10.1007/s42452-019-1413-4
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DOI: https://doi.org/10.1007/s42452-019-1413-4