Microstructural and Mechanical Properties of Aluminum Matrix Composite Reinforced with Cu-Zn-Al Particles Fabricated by Friction Stir Processing

Cu-Zn-Al particles reinforced 6061Al composites were fabricated by friction stir processing (FSP). The microstructure and mechanical properties of the composites under the FSP and T6 heat treatment were investigated. Microstructure observation showed that Cu-Zn-Al particles were homogeneously distributed in the Al matrix. FSP resulted in grain refinement and the reduction of the number of β-Mg2Si, and T6 heat treatment promoted the precipitation of fine particles (β”-Mg2Si). The introduced Cu-Zn-Al particles in the FSPed composites still exhibited reversible phase transformation between martensite and austenite. The tensile strength of the FSPed composites was inferior to that of base metal, while the elongation of composites was obviously enhanced. The tensile strengths of composites after T6 heat treatment increased greatly. The results indicated that FSP is an effective way to produce Cu-Zn-Al particles/Al composites with good mechanical properties.