Al₂O₃/Al composites consolidated from alumina and aluminum particulates by reciprocating extrusion

MMCs can be usually fabricated by powder metallurgy, stir casting and spray co-deposition, etc. Al₂O₃/Al composites were produced by means of reciprocating extrusion with alumina and pure aluminum particulates in the present study. The microstructure was analyzed by scanning electronic microscope, and the mechanical properties were measured by hardness tester and universal testing machine, respectively. The results showed that Al ₂O₃/Al composites with as high as 20 vol.% alumina can be successfully produced by reciprocating extrusion. During reciprocating extrusion process, the reinforced alumina particles can be fragmentized and uniformly distributed in the aluminum matrix. The tensile strength and hardness of the composites increase as volume fraction of alumina particles increases, whereas the elongation decreases. Compared with the pure aluminum compact, the tensile strength and hardness of the composite with 20 vol.% alumina particles is 29.3% and 93.5% higher, respectively; whereas the elongation decreases 66.6%, and the fracture mechanism of the composites is attributed to ductile rupture.