【摘要】 在Gleeble-1500热模拟试验机上对Al-6.1Zn-2.8Mg-1.9Cu-0.25Cr铝合金进行高温等温压缩实验,研究该合金在变形温度为300～500℃、应变速率为0.01～1 s-1条件下的流变行为,建立合金高温变形的本构方程,采用TEM分析变形过程中合金的组织特征。结果表明:合金变形抗力随变形温度的升高而下降,随应变速率升高而增大。在360～400℃范围内变形时,合金组织仅发生动态回复,当变形温度高于400℃以后,合金热变形以动态再结晶为主。应变速率在0.01～1 s-1范围内,不影响合金的变形软化机制,但对合金亚结构的影响较大,随应变速率的增加,位错密度增加,亚晶尺寸减少。此合金适宜的变形条件为变形温度380～400℃、应变速率0.1 s-1。更多还原

【Abstract】 The flow stress behavior of Al-6.1Zn-2.8Mg-1.9Cu-0.25Cr alloy was studied by the isothermal compression of cylindrical specimen at 300-500 ℃ and strain rate range of 0.01-1 s-1 on a Gleeble-1500 simulated machine.The thermal deformation constitutive equations were established,and the microstructure of the alloy was characterized by TEM.The results show that the flow stress decreases with the increasing of deformation temperature and increases with increasing strain rate.When the temperature range is 360-400 ℃,dynamic recovery is dominant during hot compression.However,when the deformation temperature is over 400 ℃,dynamic re-crystallization occurrs.When the strain rate is 0.01-1 s-1,no effect on deformation softening mechanism of the alloy is observed,but obvious effect of strain rate on the substructure of the alloy is examined.With the increasing of the strain rate the dislocation density increases,while the sub-grain size decreases.The recommended deformation temperature and strain rate for Al-6.1Zn-2.8Mg-1.9Cu-0.25Cr alloy are 380-400 ℃ and 0.1 s-1.更多还原