Assessment of tool wear and mechanical properties of Al 7075 nanocomposite in friction stir processing (FSP)

The aim of this study is to investigate the tool wear on friction stir processing of Al7075 base nanocomposite. The silicon carbide nanopowder was used as a reinforcing phase. The effects of input parameters including rotation speed, traverse speed and the pass number on the tool wear, microhardness and the topography were studied through the response surface methodology. Each of the input process parameters was selected in five levels, and other parameters were considered constant. The friction stir tools were examined under a scanning electron microscope, and wear mechanisms were investigated at different conditions. The analysis of variance revealed that quadratic polynomial models are fitting to predict tool wear and microhardness. In addition, the results showed that tool wear also varied between 12 and 116 mm under different parameters. Furthermore, the rotation speed and pass number of 52.9% and 13.1%, respectively, have the greatest impact on tool wear. Traverse speed with more than 55% had the most effect on microhardness comparatively. Also, energy-dispersive spectroscopy analysis showed that with the highest percentage of Fe in rotation speed 900 rpm, traverse speed 50 mm/min and with three passes, the microhardness reached the highest level of 127.24 Vickers.