Microstructure, hardness, and wear resistance of AA5083/Ti3SiC2 composites fabricated via friction stir processing

Herein, aluminum matrix composites were successfully fabricated with friction stir processing using the Al alloy 5083 as the matrix, and Ti3SiC2 MAX phase as the reinforcing particulates. The composites were fabricated using different tool rotational speeds and multi-pass approach. The microhardness and wear resistance of the AA5083/Ti3SiC2 composites were highly related to the processing parameters. The mechanical performance was directly related to the processing defects and particle distribution. Microstructural analysis using optical and scanning electron microscopy revealed that increasing the number of passes results in a more uniform distribution of Ti3SiC2 particles. The composites showed a wear rate reduction by one order of magnitude and a hardness increase from 80 to 140 Hv mean value. The wear mechanism of the AA5083 changed from severe adhesive to predominantly abrasive wear for the AA5083/Ti3SiC2 composites. Ti3SiC2 particles promoted the material transfer from the sliding counterpart; coupled with tribo-oxidation, anti-wear tribo layers were formed.