Fabrication and optimization of AA7075 matrix surface composites using Taguchi technique via friction stir processing (FSP)

In the present research, work is carried out for the parametric effects like tool rotation speed, tool profile and reinforcement in friction stir processing (FSP) of AA7075 on the microhardness and microstructural properties. The experiment design was carried out using Taguchi L 9 orthogonal array with three factors at three levels. Three different tool pin profiles viz. circular, triangular and square were used to experiment. The AA7075 matrix material was reinforced with SiC, RHA, and B 4 C. The tool rotational speed was chosen as 700, 1000 and 1300 rpm. Using the Taguchi method, the optimum level of each of these parameters was obtained. It was found that rotational speed is the most influential parameter followed by the type of reinforcement and tool profile respectively. The average microhardness of AA7075/B 4 C composite was found to be increased by 1.5–1.6 times of the base indicating that B 4 C is better compared to SiC and RHA in improving the microhardness value of the composites.