The Role of Recoil Pressure in Thermodynamic Behaviors of Molten Pool during Selective Laser Melting

Abstract

During selective laser melting (SLM) process, the recoil pressure induced by metal evaporation affects the thermodynamic behaviors of molten pool, which may result in forming defects. Taking 316L stainless steel as an example, through computational and experimental methods, the effects of the recoil pressure on the thermodynamic behaviors of the molten pool are fully investigated. The established model is based on volume of fluid (VOF) multiphase theory with full consideration of recoil pressure combining ray-tracing heat source model. From the results, with a fixed laser linear energy density, the lager the laser scanning speed, the wider the molten pool range and larger the depression depth. With a fixed laser scanning speed (1.0 m/s), the larger the laser power, the larger depression depth, which further lead to elevated depth of molten pool, but the molten pool length along scanning direction, the width and surface morphology of solidified tracks change little.