Effect of Heat Treatment on Surface Integrity and Tribological Properties of LPBF Printed AlSi10Mg

This study investigates the influence of heat treatment on the surface integrity and tribological properties of LPBF printed AlSi10Mg alloy. The AlSi10Mg samples underwent various heat treatment procedures, including stress relieving, heating the sample to 285 °C for 2 h, and direct ageing processes involving heating the sample to 170 °C for 6 h followed by furnace cooling. Comprehensive characterization was conducted using surface profilometry, scanning electron microscopy, and tribological testing. The results demonstrate significant enhancements in surface roughness and tribological properties following heat treatment. Specifically, the surface roughness of the sample treated at 170 °C for 6 h showed Sa and Sq values of 7.388 µm and 9.374 µm, respectively, compared to untreated samples which exhibited values of 8.338 µm and 10.197 µm, respectively. Heat treatment at 285 °C for 2 h led to substantial improvements in Sa and Sq values, measuring 5.523 µm and 7.000 µm, respectively. The microhardness of samples subjected to direct ageing increased by 15%, whereas stress relieving resulted in a 35% reduction in microhardness due to stress relief from the surface. Furthermore, tribological assessments under lubricating oil revealed enhanced wear resistance and reduced friction coefficients for heat-treated specimens subjected to direct ageing compared to their as printed and stress reliving counterparts. The findings underscore the efficacy of post-processing heat treatments in enhancing the surface integrity and tribological performance of LPBF printed AlSi10Mg components.