Aging behavior and microstructural stability of a Cu-8Cr-4Nb alloy

The present work investigated microstructural stability and its concurrent effect on mechanical and electrical properties of hot-rolled Cu-8Cr-4Nb alloy samples at high temperatures (600, 800 and 1000 °C) for holding durations up to 50 h. The hot-rolled samples were prepared from the near-theoretical-density hot-pressed alloy, which was made from gas-atomized powders. The hot-rolled alloy showed excellent retention of grain size due to pining of the grain boundaries, induced by the fine and homogeneously distributed stable Cr2Nb dispersoids. The yield strength and ultimate tensile strength of the samples showed no appreciable change at 600 °C and 800 °C even after 50 h, whereas, YS and UTS dropped slightly on exposure of the sample to 1000 °C for 50 h due to grain growth and coarsening of precipitates. The electrical conductivity of the samples remained almost unchanged with a slight improvement with prolonged exposure at higher temperatures.