7A55铝合金热变形的速率控制机制(英文)

利用Gleeble-3500热模拟试验机对7A55铝合金在300~450°C温度范围和0.01~1 s-1应变速率范围内的热变形行为进行研究。建立了7A55铝合金的热加工图,对该合金的热变形行为进行了遵循幂律关系的动力学速率分析。结果表明:7A55铝合金在410~450°C和0.05~1 s-1的热变形条件下发生了动态再结晶。热加工图的分析结果与动力学分析结果的吻合度较高。动态再结晶及动态回复变形的表观激活能分别为91.2和128.8 kJ/mol,这说明7A55合金的动态再结晶机制为晶界自扩散,而动态回复机制为位错的交滑移。

Rate controlling mechanisms in hot deformation of 7A55 aluminum alloy

The hot deformation behavior of 7A55 aluminum alloy was investigated at the temperature ranging from 300 ℃ to 450 ℃ and strain rate ranging from 0.01 s-1 to 1 s-1 on a Gleeble-3500 simulator. Processing maps were established in order to apprehend the kinetics of hot deformation and the rate controlling mechanism was interpreted by the kinetic rate analysis obeying power-law relation. The results indicated that one significant domain representing dynamic recrystallization （DRX） existed on the processing maps and lying in 410-450 ＆#176;C and 0.05-1 s-1. The conclusions of kinetic analysis correlated well with those obtained from processing maps. The apparent activation energy values calculated in the dynamic recrystallization （DRX） domain and the stability regions except dynamic recrystallization （DRX） domain were 91.2 kJ/mol and 128.8 kJ/mol, respectively, which suggested that grain boundary self-diffusion and cross-slip were the rate controlling mechanisms.