Session: 03-11 Metals: Simulation, Modeling, and Training I

Paper Number: 94448

94448 - Multiphysics Simulation of Multi-Layer Epitaxial Grain Growth in Laser Powder Bed Fusion of Alsi10mg Alloy 

Laser powder bed fusion (LPBF) is one of the metal additive manufacturing processes, where metal parts are built by melting metallic powders layer by layer with a high-energy laser beam. It has the great potential to be widely applied in various industries including automotive, aerospace, biomedical, energy, and other high-value low-volume manufacturing environments. However, the lack of fundamental understanding of the process-structure-property relationship for better quality control inhibits wider applications of LPBF. Recently, we developed a mesoscale multiphysics simulation approach, called phase field and thermal lattice Boltzmann method (PF-TLBM), to simulate microstructure evolution of alloys within LPBF melt pool with simultaneous consideration of solute transport, heat transfer, phase transition, and latent heat effect. In this work, the PF-TLBM model is extended to predict the multi-layer epitaxial grain growth in the complex heating and cooling environment in LPBF. The re-melting and solidification process in multiple scanning passes are simulated. To save the computational cost, the thermal history for multi-layer grain growth is approximated by an analytical model based on the Rosenthal equation. A novel marching cell simulation scheme is proposed to further reduce the computational complexity by moving the simulation domain along the building direction. The actively simulated two-dimensional domain only has a depth of heat-affected zone in the thermal model instead of modeling the complete building tank. During the layer-by-layer printing process, the stochastic nucleation model is applied and nuclei are introduced as the result of impurity and defects. The simulation results of AlSi10Mg alloy demonstrate that the PF-TLBM model is capable of simulating multi-layer printing processes in LPBF. The competitive growth of columnar dendrites is also observed in simulation results, which agree with experimental observations.

Presenting Author: Yan Wang Georgia Institute of Technology

Presenting Author Biography: Yan Wang is a Professor of Mechanical Engineering and leads the Multiscale Systems Engineering Research Group at Georgia Institute of Technology. His research areas include compute-aided design, computer-aided manufacturing, modeling and simulation, materials design, and uncertainty quantification.

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