Strategical parametric investigation on manufacturing of Al-Mg-Zn-Cu alloy surface composites using FSP

Friction stir processing (FSP) is a unique approach being presently researched for composite fabrication. In the present investigation, Al-B4C surface composite was fabricated through FSP by incorporating B4C powder particles into Al-Mg-Zn-Cu alloy (AA 7075) matrix. The influence of varying powder particle reinforcement strategies on the microstructure, powder distribution, microhardness, and wear resistance of the surface composite is reported. In addition, AA 6061/B4C composites were prepared using the same parameter set and the powder distribution in the composite was compared to that in the AA 7075/B4C composite. More homogeneous dispersion of B4C powder was observed in AA 6061 as compared to AA 7075 substrate. Among the prepared AA 7075/B4C composites, the best B4C powder distribution was detected in samples processed using fine powder and incorporating the change in stirring direction between passes. The hardness and wear resistance of the prepared composites were almost doubled attributing to several strengthening mechanisms and B4C powder distribution in the AA 7075 matrix.