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Bulk density measurement of porous functionally graded materials


Pores generated in inside of a Nickel-Alumina FGM (functionally graded material) fabricated by pressureless sintering method because of unperfected sintering. These pores change the mechanical properties of the material. To predict accurately variations of the mechanical property, there is a need for accurate measurement of porosity. Conventional method of measuring the porosity measures the outer diameter of the cylindrical specimen and calculated bulk density using it. However, this method did not consider an internal deformation of the specimen, thus the accuracy of its method is lowered. To measure a more accurate bulk density of each layer of the porous FGM than the conventional method, a method using Individual specimen and a method using the Image Processing of MATLAB (IPM) were proposed. To confirm accuracy of the proposed method, the bulk density of the entire FGM calculated by the proposed method was compared with the bulk density of the entire FGM measured by Archimedes' principle. In the comparison results, the result of the method using the IPM was closer to the result of the method using Archimedes principle than the result of the method using the Individual specimen. Thus, this author concludes that the method using IPM is more suitable for measurement of the bulk density of each layer of the FGM than the method using the individual specimens.

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D :


M :


W :


V :


ρ water :

Density of water

W 1 :

The dry weight

W 2 :

The weight in the water of the water-saturated sample

W 3 :

The weight of the water-saturated sample in air


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Correspondence to Sung-Hoon Ahn.

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Lee, JC., Ahn, SH. Bulk density measurement of porous functionally graded materials. Int. J. Precis. Eng. Manuf. 19, 31–37 (2018).

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  • Functionally graded materials (FGM)
  • Porous composite
  • Density measurement
  • Image processing