Investigation of structural formation of Al–SiC surface composite under ball collisions

An Al–SiC surface composite was fabricated on an Al surface precoated with SiC particles by ball collisions at room temperature in an ambient atmosphere. The formation of the composite was investigated at various treatment intervals between 5 and 30 min. The structural formation was affected by the treatment time, which was associated with the accumulation of strains introduced by ball collisions. In the strained zone, Al became plasticized and flowed. The Al plastic flow trapped, occluded and transported the SiC particles. Ball collisions refined the coarse grains of the initial Al plate and the SiC particles. The initial rolling texture of the Al plate, consisting of {1 1 2}〈1 1 1〉 and {1 1 0}〈1 1 2〉 orientations, was completely destroyed by 10 min of ball collisions. After 15-min treatment, the composite structure consisted of three phases: ultrafine-grained Al matrix, coarse SiC reinforcement and nanocrystalline Al–SiC composite interlayers. The hardness of the as-fabricated composite was increased almost threefold compared to that of the initial Al plate.