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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。
The Al-6.1Zn-2.8Mg-1.9Cu-0.25Cr aluminum alloy was subjected to high temperature isothermal compression test on a Gleeble-1500 thermal simulator. The results show that the alloy has the best performance at deformation temperature of 300-500 ℃ and strain rate of 0.01-1 s- 1 under the conditions of rheological behavior, the constitutive equation of the high-temperature deformation of the alloy was established, and the microstructure of the alloy during the deformation was analyzed by TEM. The results show that the deformation resistance of alloy decreases with the increase of deformation temperature and increases with the increase of strain rate. In the range of 360 ~ 400 ℃, the deformation of the alloy only changes dynamically. When the deformation temperature is higher than 400 ℃, the dynamic deformation of the alloy is dominated by dynamic recrystallization. The strain rate in the range of 0.01 ~ 1 s-1 does not affect the deformation and softening mechanism of the alloy, but has a great effect on the substructure of the alloy. With the increase of strain rate, the dislocation density increases and the subgrain size decreases. The suitable deformation conditions for the alloy deformation temperature 380 ~ 400 ℃, strain rate 0.1 s-1.