A three-phase model for simulation of heat transfer and melt pool behaviour in laser powder bed fusion process

Laser powder bed fusion (LPBF) is one of the most promising additive manufacturing technologies to fabricate high quality metal parts. In this work, a three-phase model based on the volume of fluid (VOF) is employed to investigate the heat transfer and melt pool behaviour in LPBF. Surface tension, Marangoni effect and recoil pressure are implemented in the model, and heat adsorption, reflection and transmission are fully considered. The results show that the melt pool dimension and its shape are controlled by laser power and scanning speed. Metal powders at the bottom layers may be not fully melted, and for larger layer thickness of the powder bed, porosities caused by the trapped gas can form. The gas originated from bulk powders can dissolve, coalesce, and be squeezed in the melt pool. It is demonstrated that the model can capture the main features of powder melting and solidification in LPBF process. [Display omitted] •Melt pool dynamics in powder bed fusion process is investigated mathematically.•A deeper depression region is produced by considering multiple reflection.•Porosities caused by the trapped gas can form for larger depth powder bed.•Gas originated from bulk powders can dissolve, coalesce, and be squeezed in melt pool.