Laser powder bed fusion processing of plasma atomized AlSi10Mg powder: Surface roughness and mechanical properties modification

Abstract

In the quest for seeking aluminum alloys with high printability, AlSi10Mg alloy has been sought as one of the most promising candidates for the laser powder bed fusion (LPBF) technique. Despite the extensive research conducted in LPBF AlSi10Mg, the development of printing parameters to obtain a combination of low porosity and roughness, as well as the desired combination of strength, elongation, and fatigue properties, is considered as one of the most significant difficulties to meet the minimum requirements specified in the standards. Due to the high surface roughness observed in the printed samples using standard printing parameters, this research aims to obtain a combination of low roughness and porosity, as well as excellent tensile and fatigue properties through the development of printing parameters including layer thickness, laser power, scan speed, and hatch distance. Among the developed parameters, decreasing the layer thickness from 60 μm to 50 μm considerably mitigated the surface roughness with the laser power (360 W), scan speed (1550 mm/s), and hatch distance (150 μm). In addition, the optimal stress relief heat treatment at 285 °C for 240 mins was determined for the proposed 50 μm layer thickness to meet the tensile test requirements.