Track-scale Anisotropic Thermal Material Model as a Viable Substitution In Selective Laser Melting

Abstract

High temperature gradients and resulting residual stresses are the main sources of defects such as cracks, distortion and fatigue failure is selective laser melting. In this paper, a new material model utilizing anisotropic thermal conduction model and track-scale heat input model is used to predict the melt pool geometry, material state and thermal history during the SLM process of SS316L in a large range of laser parameters. The model takes into consideration both the material state and the issue of phase transition during the track-scale simulation.. The simulated melt pools in the beam-scale and track-scale simulations are compared with experimental measurements in different laser parameters. It is found that the proposed material model is able to maintain accuracy between the beam-scale and track-scale simulations at an average of 5μm regarding melt pool dimensions. Furthermore, It can be inferred that both track-scale and beam-scale models exhibit the capability to provide precise predictions of melt pool geometries when compared to experimental measurements while the former being about 100 times faster than the latter. An average error of 10% was concluded for the material state comparison of the two models while the track-scale model was able to capture the temperature profile and cooling rate accurately in comparison with the beam-scale model.