| Summary: | A new type of Al/Cu bimetallic foams with double grade plateau stresses was prepared by employing powder metallurgy sintering method. The addition of CuSn _33 is to improve the microstructure and mechanical properties of Al/Cu bimetallic foams. The effects of CuSn _33 content on the phase components, lattice parameter, crystallize size and microstrain of Cu-matrix were investigated with utilizing Rietveld method. Results show that there is a linera relationship between CuSn _33 content and lattice parameter, and the linear fitting equation was also simulated. The addition of CuSn _33 can refine the crystallite and increase the microstrain when the Sn with larger atomic radius dissolves into Cu-matrix alloy. However, the microstrain value drops dramatically when the precipitated δ -phase appears from the supersaturated solute elements. Segregation caused by the residual Sn in the Cu-matrix primarily appears near to the border of Al _2 Cu and Cu-matrix. The compressive stress-strain curves of Al/Cu bimetallic foams with 5 typical stages are radically different from the single component metal foams, including twice quasi-linear regions, twice collapse plateaus, and the densification region. The effects of CuSn _33 content on the elastic modulus of Al/Cu bimetallic foams, microhardness of Cu-matrix and the absorbed energy density have also been investigated.
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