Constitutive modeling, processing map establishment and microstructure analysis of spray deposited Al-Cu-Li alloy 2195

Abstract

The hot compression tests for spray deposited alloy 2195 were performed on Gleeble-1500 thermomechanical simulator at different conditions. The constitutive models and processing map of the alloy were established. The deformation mechanisms at different areas of the processing map were revealed via metallographic and electron backscatter diffraction examinations of the compressed samples. The results showed that dynamic precipitation of Al2CuLi phase occurred at low deformation temperatures (400–450 °C). The precipitation caused significant reduction in solution strengthening effect, resulting in rapid decrease of flow stress. The instability domain at low temperature was induced by the decreasing flow stress. Moreover, the stacking faults with the precipitation of Al2CuLi caused the discontinuous dynamic recrystallization. The precipitation and recrystallization led to the high dissipation efficiency at low temperature and low strain rate. At high temperatures (500–550 °C), the deformation mechanisms varied with the imposed strain rates. The dynamic recovery and recrystallization occurred at strain rate of 0.1–1 s−1, which led to the high dissipation efficiency. At low strain rate (0.01–0.1 s−1), the alloy exhibited strong dynamic recovery characteristic, which caused the decrease in dissipation efficiency. The deformation instability occurred when the strain rate is about 10 s−1, and intergranular cracking was the main instability mechanism.