A high temperature nanoindentation study of Al-Cu wrought alloy

Aluminum-copper alloys are widely used because of their low density and good mechanical strength accomplished with precipitation hardening. The alloy Al-Cu-Mg-Pb (AA2030) has been investigated before and after aging, at room temperature and at high temperatures. The mechanical properties at room temperature have been studied by Brinell hardness tests. T4 and T6 stages of the alloy have been investigated by differential scanning calorimetry up to 450°C, showing the precipitation of different clusters. High temperature nanoindentation has been used to characterize the mechanical properties up to 460°C in order to obtain a better understanding of the local dominating deformation mechanism in the material. A continuous decrease in the hardness and Young's modulus was found with the increasing temperature. The strain rate sensitivity of the alloy increased with the temperature from 0.022 at RT, up to 0.16 at 460°C. The activation volume was constant (around 31-41b³) up to 240°C, beyond this point a large increase was observed up to 178b³. The results were comparable with similar materials, and indicate thermally activated processes.