Aluminum Matrix Composites Reinforced with Cu9Al4 Particles: Mechanochemical Synthesis and Consolidation by the Spark Plasma Sintering

X-ray analysis and scanning electron microscopy have been used to study mechanochemically synthesized Al/10 wt % Cu9Al4 and Al/20 wt % Cu9Al4 composites and sintered materials based on them. As a modifiers, powders of the mechanosynthesized nanostructured Cu9Al4 intermetallic compound were used. It has been shown that the composite structure with the uniform distribution of the Cu9Al4 particles in the aluminum matrix is formed during mechanical activation even for 1 min. In the course of mechanical activation of the powder mixtures of Al with 10 and 20 wt % Cu9Al4 the size of intermetallic crystallites grows by 2.3-3 times to 7 and 9 nm, respectively. After spark plasma sintering of the Al/Cu9Al4 composites, the uniform distribution of reinforcing particles retains for their content up to 20 wt %. The hardness of sintered composites is 60-77 HV, which is similar to 2 times higher than the hardness of aluminum without additives of the strengthening phase.