Abstract
A mesoscopic model was established to investigate thermo-fluid dynamic behavior in selective laser melting of 316L stainless steel. A powder packing model, including particle size distribution based on the discrete element method, was developed to describe the relative density variation of the powder bed with different layer thicknesses. A finite element method model with Gaussian laser beam was established to predict the dynamic thermal behavior and flow mechanism of the particles for a single-line scanning. The level-set method was used to trace the free surface of the molten metal with temperature-dependent surface tension. A function to describe the relative density of the powder bed with its thickness was obtained. An evaporation model considering the influence of mass, energy loss, and evaporation on the surface morphology of the molten pool was established. According to the temperature and velocity field in the molten pool, a vortex formed by the Marangoni effect might decrease the depth and increase the width of the molten pool. The molten pool was not disconnected by Plateau–Rayleigh instability due to the small length/diameter ratio at low scanning speeds. The model assuming regularly arranged powder bed underestimates the maximum temperature as compared to the model considering a randomly packed powder bed because a higher relative density of the former facilitates heat conduction. The simulated results are consistent with experimental results, including porosity, material loss, and surface defects.
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References
B. Schoinochoritis, D. Chantzis, and K. Salonitis, Simulation of Metallic Powder Bed Additive Manufacturing Processes with the Finite Element Method: A Critical Review, Proce. Inst. Mech. Eng. Part B J. Eng. Manuf., 2017, 231, p 96–117. https://doi.org/10.1177/0954405414567522
C. Panwisawas et al., Mesoscale Modelling of Selective Laser Melting: Thermal Fluid Dynamics and Microstructural Evolution, Comput. Mater. Sci., 2017, 126, p 479–490. https://doi.org/10.1016/j.commatsci.2016.10.011
S.A. Khairallah et al., Laser Powder-Bed Fusion Additive Manufacturing: Physics of Complex Melt Flow and Formation Mechanisms of Pores, Spatter, Denudation Zones, Acta Mater., 2016, 108, p 36–45. https://doi.org/10.1016/j.actamat.2016.02.014
W.E. King et al., Laser Powder Bed Fusion Additive Manufacturing of Metals; Physics, Computational, Materials Challenges, Appl. Phys. Rev., 2015, 4, p 041304. https://doi.org/10.1063/1.4937809
C. Körner, A. Bauereiß, and E. Attar, Fundamental Consolidation Mechanisms During Selective Beam Melting of Powders, Modell. Simul. Mater. Sci. Eng., 2013, 21, p 085011
S. Shrestha and K. Chou, A Build Surface Study of Powder-Bed Electron Beam Additive Manufacturing by 3D Thermo-fluid Simulation and White-light Interferometry, Int. J. Mach. Tools Manuf., 2017, 121, p 37–49. https://doi.org/10.1016/j.ijmachtools.2017.04.005
D. Dai and D. Gu, Thermal Behavior and Densification Mechanism During Selective Laser Melting of Copper Matrix Composites: Simulation and Experiments, Mater. Des., 2014, 55, p 482–491. https://doi.org/10.1016/j.commatsci.2016.10.011
F.J. Gürtler et al., Simulation of Laser Beam Melting of Steel Powders using the Three-Dimensional Volume of Fluid Method, Phys. Proc., 2013, 41, p 881–886. https://doi.org/10.1016/j.phpro.2013.03.162
S.A. Khairallah and A. Anderson, Mesoscopic Simulation Model of Selective Laser Melting of Stainless Steel Powder, J. Mater. Process. Technol., 2014, 214, p 2627–2636. https://doi.org/10.1016/j.jmatprotec.2014.06.001
Y.S. Lee and W. Zhang Mesoscopic Simulation of Heat Transfer and Fluid Flow in Laser Powder Bed Additive Manufacturing, in International Solid Freeform Fabrication Symposium. Austin, TX; p. 1154–1165 (2015).
K.H. Leitz, et al. Multi-Physical Simulation of Selective Laser Melting of Molybdenum, in Proceedings of Euro Pm 2015; p. 4–7.
K.H. Leitz et al., Thermo-Fluid dynamical Simulation of Layer Buildup by Selective Laser Melting of Molybdenum and Steel, BHM Berg-und Hüttenmännische Monatshefte, 2017, 162, p 172–178. https://doi.org/10.1007/s00501-017-0588-5
K.H. Leitz et al., Fundamental Analysis of the Influence of Powder Characteristics in Selective Laser Melting of Molybdenum Based on a Multi-physical Simulation Model, Int. J. Refract Metal Hard Mater., 2018, 72, p 1–8. https://doi.org/10.1016/j.ijrmhm.2017.11.034
D.Q. Zhang et al., A Powder Shrinkage Model for Describing Real Layer Thickness during Selective Laser Melting Process, Advanced Materials Research, 2010, 97, p 3820–3823. https://doi.org/10.4028/www.scientific.net/AMR.97-101.3820
S.I. Anisimov, High Temp. 6th ed (1968).
M. Courtois et al., A New Approach to Compute Multi-reflections of Laser Beam in a Keyhole for Heat Transfer and Fluid Flow Modelling in Laser Welding, J. Phys. D Appl. Phys., 2013, 46, p 505305
S. Shrestha and K. Chou, Mesoscopic Multilayer Simulation of Selective Laser Melting Process, in 28th Annual International Solid Freeform Fabrication (SFF) Symposium—An Additive Manufacturing Conference, Austin August 7–9.
J. Eggers, Nonlinear Dynamics and Breakup of Free-Surface Flows, Rev. Mod. Phys., 1997, 69, p 865–929. https://doi.org/10.1103/RevModPhys.69.865
D. Schwabe and A. Scharmann, Thermocapillary Convection in Crystal Growth Melts, Lett. Heat Mass Transfer, 1980, 7, p 283–292
A.I. Mizev and D. Schwabe, Convective Instabilities in Liquid Layers with Free Upper Surface Under the Action of an Inclined Temperature Gradient, Phys. Fluids, 2009, 21, p 112102
G. Phanikumar, K. Chattopadhyay, and P. Dutta, Modelling of Transport Phenomena in Laser Welding of Dissimilar Metals, Int. J. Numer. Methods Heat Fluid Flow, 2001, 11, p 156–174. https://doi.org/10.1103/RevModPhys.69.865
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This work was supported by the National Natural Science Foundation of China (51304214).
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Liu, L., Huang, M., Ma, Y.H. et al. Simulation of Powder Packing and Thermo-Fluid Dynamic of 316L Stainless Steel by Selective Laser Melting. J. of Materi Eng and Perform 29, 7369–7381 (2020). https://doi.org/10.1007/s11665-020-05230-w
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DOI: https://doi.org/10.1007/s11665-020-05230-w