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在变形温度为300～460℃,应变速率为0.001～1.000s-1的条件下,采用Gleeble-1500热模拟试验机对7B50铝合金的热变形加工行为进行了研究。结果表明,7B50铝合金在热压缩变形中的流变应力随着温度的升高而减小,随着应变速率的增大而增大。对该合金进行热变形加工的适宜条件是:热压缩加工温度为380～460℃、应变速率为0.100～1.000s-1。在变形温度较高或应变速率较低的合金中发生部分再结晶,并且在合金组织中存在大量的位错和亚晶。随着温度升高和应变速率降低,亚晶尺寸增大,位错密度减小,合金的主要软化机制逐步由动态回复转变为动态再结晶。
The hot deformation behavior of 7B50 aluminum alloy was investigated by Gleeble-1500 thermal simulator under the conditions of deformation temperature of 300 ~ 460 ℃ and strain rate of 0.001 ~ 1.000s-1. The results show that the flow stress of 7B50 aluminum alloy decreases with the increase of temperature and increases with the increase of strain rate. The optimum conditions for the hot deformation of the alloy are as follows: the hot compression temperature is 380 ~ 460 ℃, the strain rate is 0.100 ~ 1.000s-1. Partial recrystallization occurs in the alloy with higher deformation temperature or lower strain rate, and there is a large amount of dislocations and subgrains in the alloy structure. As the temperature increases and the strain rate decreases, the size of the subgrain increases and the dislocation density decreases. The main softening mechanism of the alloy gradually changes from dynamic recovery to dynamic recrystallization.