2A14铝合金热变形的显微组织及流变行为

Microstructure and flow behavior of 2A14 aluminum alloy during hot deformation

在Gleeble-3500热模拟机上对2A14铝合金进行热压缩实验，研究该合金在变形温度为350-480℃、应变速率为0.001-10 s-1条件下热压缩变形的显微组织特征和流变应力行为。采用光学显微镜（OM）和透射电镜（TEM）对变形后的显微组织进行表征。结果表明：随着应变速率的降低和变形温度的升高，合金中拉长的晶粒粗化，发生部分动态再结晶，合金的主要软化机制由动态回复向动态再结晶转变；合金的流变应力随变形温度的升高和应变速率的降低而减小。合金热变形的流变应力行为可用双曲正弦形式的本构方程来描述，也可用Zener-Hollomon参数来描述，其变形激活能为173.375 kJ/mol。

The flow stress behavior of 2A14 alloy during hot compression deformation was investigated by thermal simulation experiment at the temperature range of 350-480 ℃ and the strain rate range of 0.001-10 s-1 with Gleeble-3500 thermal simulation machine. The deformation microstructures were observed by optical microscopy （OM） and transmission electron microscopy （TEM）. The results show that the elongated grains coarsen with decreasing strain rate and increasing temperature. The partial recrystallization takes place in the alloys deformed at high temperature or low strain rate. The main soften mechanism of the alloy transforms from dynamic recovery to dynamic recrystallization. The flow stress reduces with the increasing deformation temperature and decreasing strain rate. The flow stress of the alloy during hot compression deformation can be described by constitutive equation in hyperbolic sine function and can also be described by Zener-Hollomon parameters, and the hot deformation activation energy is 173.375 kJ/mol.