Effect of Heat Treatment on Microstructure and Performance of Laser Power Bed Fusion Processed Sc and C Element Modified Alsi10mg Alloy

Abstract

This study investigated the laser powder bed fusion (LPBF) processed AlSi10Mg alloy modified by Sc and C elements, and explored the impact of heat treatment on its microstructure and properties. After solution treatment at 500°C for 3 h followed by aging at 150°C for 6 h, the grain size becomes smaller and more uniform, contributing to enhanced mechanical and corrosion properties. The self-corrosion potential (Ecorr) of alloy reaches -0.6536V, with a self-corrosion current (Icorr) of 3.528×10-7A/cm2, indicating a significant boost in corrosion resistance. The alloy had the highest average hardness (HV 91.7) after a 3h solution treatment at 500°C and a 3h aging treatment at 200°C, which was attributed to the uniform dispersion of the Si phase in the α-Al matrix. Atomic force microscopy (AFM) results shew that the surface roughness is minimized after the 500°C+3h solution treatment and 150°C+6h aging treatment, with a Ra value of only 5.17nm. Neutral salt spray testing (SST) in simulated marine environments further validates that optimizing the heat treatment process effectively enhances the corrosion resistance of alloys. Overall, the combined modification of Sc and C, and heat treatment provides an effective approach to improve the performance of AlSi10Mg alloy.