Investigation of work softening mechanisms and texture in a hot deformed 6061 aluminum alloy at high temperature

摘要

Hot deformation behavior of 6061 aluminum alloy was investigated by performing compression test in the temperature range of 350-500 ℃. Equivalent strain rates were selected in the range of 0.0005-0.5 s~(-1) in order to obtain processing and stability maps of the studied material using a Dynamic Material Model. Microstructure of the samples after deformation was analyzed by light and electron microscopy and the differences were compared together. The stresses obtained from the flow curves were related to strain rate (ε) and temperature (T) by a constitutive equation in hyperbolic sine function with hot deformation activation energy of 274 kJ/mol, and were described by the Zener-Hollomon equation. Microstructure results showed that with decreasing Z value, the elongated grains coarsened and the tendency of dynamic recrystallization enhanced. Correspondingly, the subgrain size increased and the dislocation density decreased. Moreover, the main softening mechanism of the alloy transformed from dynamic recovery to dynamic recrystallization. XRD results showed that the (200) texture has an important role in development of dynamic recystallization at high temperature.