Preparation of Al₂Cu/Al composites by mechanical alloying and spark plasma sintering

The bulk dense Al₂Cu/Al composites were prepared in situ by mechanical alloying (MA) and spark plasma sintering (SPS), using Al and Cu powders as raw materials.The variation of morphology, size and phase structure of powders during the MA process was studied.The microstructure and the mechanical properties of composites after SPS process were investigated.The results show that with the increase of MA time in MA process, some amount of Cu atoms gradually diffuse into Al atomic lattice to form a homogeneous supersaturated Al (Cu) solid solution.During SPS process, Cu atoms precipitate from supersaturated solid solution and then react with Al to form Al₂Cu particles uniformly distributed in Al matrix and Al₂Cu/Al composites are formed.The density of Al₂Cu/Al composites reaches up 98.7%.It exhibits good mechanical properties with high fracture strength (611.3 MPa) and large plastic strain (9.6%) at room temperature.