Enhanced combination properties of Cu-0.8Cr alloy by Fe and P additions

Abstract

With the goals of exploring the feasibility of replacing Zr with Fe and P in Cu–Cr–Zr alloys and developing Cu–Cr–Fe–P alloys with excellent mechanical and electrical properties, the effects of Fe and P additions on the microstructures and properties of the as-cast, cold-rolled and aged Cu-0.8Cr alloys are investigated. The results indicate that adding Fe and P into the Cu-0.8Cr alloy can promote the precipitation of a large amount of fine, uniformly dispersed Cr and Cr3P particles. From Cu-0.8Cr to Cu-0.8Cr-0.17Fe-0.048P, the area fraction of precipitates increases from 3.1% to 6.3% while their average diameter reduces from 1.6 μm to 1.4 μm. When subjected to 95% cold rolling plus 450 °C aging for 1 h, the Cu-0.8Cr-0.17Fe-0.048P alloy exhibits a Vickers hardness of 140.4 HV and an electrical conductivity of 73.2%IACS, higher than 96.7 HV and 58.4%IACS in the Cu-0.8Cr alloy. Among three different processing routes investigated, the one with initial 50% cold rolling → aging at 500 °C for 1 h → final 95% cold rolling allows the Cu-0.8Cr-0.17Fe-0.048P alloy to gain most in both its tensile strength (569 MPa) and electrical conductivity (64%IACS). The findings in this work provide insights to composition and processing designs for new Cu–Cr alloys with high strength and electrical conductivity.