Strengthening mechanism of surface-modified SiCp/Al composites processed by the powder-in-tube method

Abstract The powder-in-tube method was used to investigate the strengthening mechanism of surface-modified SiC p /Al composites at room temperature. A typical amorphous Al 2 O 3 layer was formed for the untreated SiC p /Al composite (C USiC ). Obvious interfacial cracks were generated in the pre-oxidized SiC p /Al composite (C OSiC ), because of the insufficient activation energy for the reaction between SiO 2 and Al. Comparatively, the interfacial strength of the Cu-coated SiC p /Al composite (C Cu-SiC ) was significantly enhanced by the formation of the CuAl 2 phase. The composite reinforced by the low content Cu-coated SiC (6 wt%) exhibiting an ultimate strength of 196 MPa (+ 50.7% compared to the Al matrix) was processed by the low-speed and short-time ball milling process followed by the pack rolling at room temperature. For C USiC , load transfer and grain refinement were the main strengthening mechanism. While for C Cu-SiC , the precipitation strengthening of tiny CuAl 2 phase (0.6 vol.%) contributed to ∼77% to the total strength increase.