Microstructure and properties of a Cu–Cr–Zr alloy

Copper-based dilute Cu–Cr–Zr alloys and their minor modifications, because of their excellent thermal conductivity, strength and fatigue resistance, are commonly used in an aged condition in heat transfer elements. However, in comparison to dilute Cu–Cr binary alloys in which the precipitation of chromium has been studied extensively in the last two decades, attempts at delineating the morphology, composition and crystallography of precipitates in Cu–Cr–Zr alloys have been few and only partially successful. The role of zirconium has also remained largely unresolved. In the present work, the precipitation in an alloy having a nominal composition of Cu–1 wt% Cr–0.1 wt% Zr has been shown to take place through the formation of a metastable ordered fcc phase. Also, the improvement in fatigue resistance due to the addition of zirconium has been ascribed to lowering of the stacking fault energy (SFE) of the alloy.