Effect of Si on the microstructure and mechanical properties of as drawn Cu–15Cr in situ composites

0.5 mass% Si has been added into the Cu–15Cr based alloy for the purpose of strengthening. The microstructure and properties of Cu–15Cr–0.5Si in situ composites have been investigated. Because of the effective hardening to Cr phase due to the addition of Si, both the thickness of Cr fibres and the interphase spacing are larger than the previous results in Cu–15Cr in situ composites at the same drawing strain, therefore, the drawn structure is coarser due to the addition of Si. In addition to dissolving in Cu and Cr phases, Si also reacts with Cr to form Cr3Si (accounts for 4 vol.%), which is brittle and was broken during the following cold deformation. The hardness of both Cu and Cr phases in the as drawn wire increases with increasing drawing strain by work hardening. The tensile strength of as drawn Cu–15Cr–0.5Si in situ composites is superior to that of Cu–15Cr binary in situ composites only when the drawing strain is lower than 4.5.