Enhanced micro-hardness and wear resistance of Al-15Si/TiC fabricated by selective laser melting

High relative density (>98%) Al-15Si alloy samples were fabricated by selective laser melting (SLM) with laser re-melting process. The micro-hardness and wear resistance of Al-15Si alloy samples were investigated in this study. The addition of 5 wt% TiC improved the micro-hardness of SLM-produced Al-15Si alloy, which had a remarkable micro-hardness of 172.8 Hv. After the heat treatment (annealing or quenching), the hardness of all tested samples decreased significantly, while the Al-15Si/TiC composites with the laser re-melting kept the higher hardness values (145 Hv). This sample presented the lower coefficient of friction (0.42) and wear rate (2.75 × 10-5 mm3 N-1 m-1) than other conditions. Based on the results, the addition of 5 wt% TiC with laser re-melting in SLM process, together with annealing treatment afterwards, was a feasible approach to obtain a high micro-hardness and good wear resistance of Al-15Si alloys.