Microstructures and properties of Cu-10Cr-0.4Zr In-situ composites

The Cu-10Cr alloy,Cu-10Cr-0.4Zr alloy and the in-situ composite based on the alloy were prepared. Microstructures of as-cast,evolution of filaments,strength and electrical conductivity of Cu-10Cr and Cu-10Cr-0.4Zr in-situ composites have been investigated. The results show that the addition of 0. 4wt%Zr in the Cu-10wt%Cr gives birth to smaller as-cast Cr dendrites,their diameters were reduced from 15-80μm to 10-20μm;at the same draw ratio,Cu-10Cr-0.4Zr composites have larger intrinsic friction stress,finer filaments and spacing between the filaments than Cu-10Cr composites,and the ultimate strength of Cu-10Cr-0.4Zr composites reaches 1089MPa at draw ratio of η=6.2,however that of the same processed Cu-10Cr is only 887MPa;and at the same draw ratio,the electrical conductivity of Cu-10Cr composites is little higher than that of Cu-10Cr-0.4Zr composites,the decreasing electrical conductivity is caused by the transition of resistivity contribution from dislocation scattering to interface scattering in the Cu matrix.