A Simulation Study on the Effect of Residual Stress on the Multi-Layer Selective Laser Melting Processes Considering Solid-State Phase Transformation.

The selective laser melting (SLM) manufacturing process is a complex process involving moving a molten pool, rapid non-equilibrium solidification and solid phase transformation. If the thermal residual stress is too large, it may lead to warping, cracking and failure of the structures. The present work aims to establish a thermo-mechanical framework to predict temperature evolutions, molten pool configurations and residual stresses of materials in the SLM process, based on the toolpath-mesh intersection method. Moreover, the influences of the laser power, process parameters and mesh size have been discussed. The stress concentration occurred at the interface between the melt layer and substrate results in warping deformation of the materials. This work provides a novel method to reveal the resulting physical mechanism inside the molten pool in terms of residual stresses and distortions.