A thermodynamically consistent non-isothermal phase-field model for selective laser sintering

CG Liang and Y Yin and WX Wang and M Yi, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 259, 108602 (2023).

DOI: 10.1016/j.ijmecsci.2023.108602

Selective laser sintering (SLS) additive manufacturing possesses the characteristics of extremely non-uniform temperature distribution and high temperature gradient, which are unmanageable by the traditional isothermal models. In this work, we propose a thermodynamically consistent non-isothermal phase-field model (PFM) to investigate the microstructure evolution during SLS process with the full consideration of temperature gradient effect. The model is derived from a thermodynamic framework which invokes the microforce theory and Coleman- Noll procedure. The temperature-dependent parameters in the free energy formulation are determined by the experimentally measurable surface energy and grain boundary energy with a given interface width. Benchmark simulations of sintering two particles under temperature gradient indicate that the grain boundary has the trend to migrate to the higher temperature region, which is further verified by molecular dynamics simulations. This phenomenon cannot be captured by the traditional isothermal PFM. Grain boundary migrations can also be driven by curvature for two unequally-sized particles. Simulations on SLS of powder bed show the dependence of microstructure evolution and final porosity on the laser power and scanning speed. The developed non- isothermal PFM could be a practicable toolkit for the microstructure simulation of SLS process.

Return to Publications page