Part-scale multi-physics model for laser powder bed fusion process

<h2>Summary</h2> A part-scale multi-physics (PS-MP) model has been developed to overcome computational efficiency challenges in simulating laser powder bed fusion (L-PBF). This framework enables simulations of laser scanning over 10,000 tracks, facilitating virtual construction of cubic-centimeter-scale intricate structures. The four critical principles for model validations ensure reliable high-fidelity replication of process-specific characteristics while simultaneously capturing three mechanical performance determinants: surface topography, volumetric defects, and microstructure characteristics elucidated by the PS-MP model. Here, we report findings on the fundamental mechanisms of L-PBF process, including the evolution of surface topography and its correlation with lack-of-fusion pores, the formation mechanisms of subsurface pore defects, the grain growth during columnar-to-equiaxed transition in AlMgScZr alloys, and the martensitic phase transformation in TC4 alloys. The PS-MP modeling framework directly addresses sustainable manufacturing through full-process chain simulation, potentially reducing material waste from trial-and-error experiments.