Investigation of mechanical and tribological behavior of SiC and B4C reinforced Al-Zn-Mg-Si-Cu alloy matrix surface composites fabricated via friction stir processing

In this study, SiC and B4C reinforced Al-Zn-Mg-Si-Cu alloy matrix surface composites (SCs) were produced by friction stir processing (FSP) technique. Microstructural, mechanical, and tribological properties of produced SCs, and those of non-reinforced samples were examined. In B4C and SiC reinforced SCs fabricated by friction stir processing, approximately a 20% increase in hardness was achieved as compared to the base metal. The maximum microhardness values of B4C and SiC reinforced surface composites were determined as 88.1 and 89.7 HV, respectively. The tensile strengths of these samples were measured as 166.42 and 174.74 N·mm−2, respectively. As a result of the tests performed under 3, 5, and 10 N applied loads, it was observed that the friction coefficient decreased in general with the applied load. A higher coefficient of friction was obtained in SiC reinforced SCs than those of B4C reinforced SCs and non-reinforced samples. It was determined that the wear rate of B4C reinforced SCs decreased by ~30–40% and SiC reinforced SCs by ~50–55% compared to non-reinforced samples. In the examinations, it was revealed that mechanically mixed layer formation effectively reduced wear rate in these samples compared to non-reinforced samples.