On the serrated flow of Al-Cu solid solution alloys

Abstract

Tensile tests were performed on Al-0.5 at.%Cu and Al-1 at.%Cu solid solution alloys. The effects of temperature and strain rate on the serrated flow were investigated. The relation of ε∝ε₀^2.1 was obtained at temperatures below 22°C, in which ε is the strain rate and ε₀ is the strain at the start of serrated flow. At these temperatures, the value of activation energy for vacancy migration obtained was O.5 eV. The form of the serrated flow was different at between the temperatures of above and below 22°C. When the flow stress was plotted as a function of temperature, the peaks on the curves appeared at about 50 and 75°C for Al-0.5 at.%Cu and Al-1 at.%Cu alloys, respectively. The temperature at which change in the form of the serrated flow occurred corresponded with that at which the flow stress began to increase with the rise in temperature.