6005A与6082铝合金热变形流变行为

利用Gleeble-1500热模拟试验机对6005A和6082铝合金进行高温等温压缩试验，研究了在变形温度为450-550℃和应变速率为0．005-10s^-1条件下两种铝合金的热变形流变行为．6005A铝合金在低应变速率条件下，不同变形温度时的流变曲线均呈现波浪形特征，随着应变速率的增加，硬化和软化接近平衡，表现为稳态流变特征；在高应变速率条件下，硬化过程占据主导地位，回复和硬化过程的竞争使流变曲线呈现波浪形上升的趋势．6082铝合金在低应变速率情况下，不同变形温度时的流变曲线未出现周期性波动；在中等应变速率条件下也表现为稳态流变特征；在高应变速率条件下出现波浪形特征．两种铝合金均为正应变速率敏感材料，其热变形是受热激活控制．最后给出了铝合金热变形条件下流变应力、应变速率和变形温度三者之间的关系式．

Flow behaviors of 6005A and 6082 aluminum alloys during hot deformation

The flow behaviors of 6005A and 6082 aluminum alloys were investigated by high-temperature isothermal compression on a Glebble-1500 thermal-mechanical simulator at deformation temperatures of 450 to 550 ℃ and strain rates of 0.005 to 10s-1.The flow stress curve of 6005A aluminum alloy exhibits a waveform character at different deformation temperatures under the condition of low strain rate.With increasing strain rate the competition between softening and hardening closely reaches to a balance so that the flow stress appears as a steady state.At high strain rate,the hardening is dominant during the hot deformation and there is a waveform increase in the flow stress curve because of the competition between reverting and hardening.The flow stress curve of 6082 aluminum alloy,however,does not show the waveform character at low strain rate.A steady-state stress is also displayed at medium strain rate.But the waveform flow curve is shown at high strain rate.Both of the alloys are positive strain rate sensitive materials and their hot deformation is controlled by the thermal activation.Finally the relationships among flow stress,strain rate and deformation temperature were proposed for 6005A and 6082 aluminum alloys,respectively.