6A02铝合金动态再结晶临界模型研究

Investigation on critical model of dynamic recrystallization for 6A02 aluminum alloy

为了探究工艺参数对6A02铝合金临界发生的影响,采用Gleeble1500D型热模拟试验机对6A02铝合金在683~783K和应变速率0.001~1s^(-1)内进行等温热压缩实验,基于E.I.Poliak和J.J.Jonas提出的动态再结晶临界动力学理论,及真应力-应变数据确定其动态再结晶临界发生条件。结果表明,动态再结晶临界应变(ε_c)与峰值应变(ε_p)的相关关系为ε_c=0.667εp,通过引入应变速率温度补偿因子(即Zener-Hollomon参数,又称Z参数)建立了该合金动态再结晶临界发生模型:ε_c=2.355×10^(-4) Z^(0.1519)。变形温度的提高和变形速率的降低能够促进6A02铝合金动态再结晶行为的发生,所建立动态再结晶临界模型获得的结果与热压缩实验结果吻合良好,表明该临界模型可以较准确地预测6A02铝合金热成形过程中动态再结晶发生的临界条件。

The flow stress behavior of 6A02 aluminum alloy during hot deformation was investigated at temperature of 683？783 K and strain rates of 0. 001-1 s-1 on the Gleeblel500D thermal simulation test machine with the help of the critical condition theory proposed by E. I. Poliak and J. J. Jonas. Based on the analysis of true stress-strain curves, the critical condition of dynamic recrys-tallization was confirmed. The results show that there is linear relationship between critical strain and peak strain, i. e. εc/εp = 0. 667. It is also shown that the critical condition model was established by employing temperature compensation factor （Z） ： εc = 2. 355×10-3Z0.1519. The results show that the occurrence of dynamic recrystallization behavior will be promoted with the de-crease of strain rate and the increase of deformation temperature. The results show that comparisons between the simulated and experimental results are satisfactory, and the critical model could be used for indicating the critical condition of dynamic recrystal-lization for 6A02 aluminum alloy.