6061铝合金热变形动态再结晶行为研究

Dynamic Recrystallization Behavior of 6061 Aluminum Alloy

利用Gleeble-3500试验机对6061铝合金进行单道次等温恒应变速率压缩试验,研究合金在应变速率为0.001～1s^(-1),温度为350～500℃热变形条件下的动态再结晶行为。统计试验所得流变应力曲线峰值应力数据,确定合金热变形激活能Q为307.528kJ·mol^(-1),建立合金在不同热变形条件下的流变应力方程,动态再结晶峰值和临界应变模型;依据流变应力曲线特征,计算合金在不同变形条件下的动态再结晶体积分数,据此建立动态再结晶动力学模型。分析流变应力曲线可知铸态6061铝合金在350～500℃下变形,应变速率较低时(<0.01s^(-1)),合金组织更容易发生动态再结晶,应力软化现象更明显。

A single isothermal constant strain rate compression test was carried out for 6061 aluminum alloy by the Gleeble-3500 simulator to understand the dynamic recrystallization behavior of the alloy under thermal deformation conditions at 0.001～1 s-1 and 350～500 ℃.The peak stress data of the rheological stress curve obtained from the statistical test determines that the thermal deformation activation energy of the alloy is Q=307.528 kJ·mol-1,and the rheological stress equation,dynamic recrystallization peak and critical strain model under different thermal deformation conditions are established.The dynamic volume fraction of the alloy was calculated under different deformation conditions according to the rheological stress curve,and the dynamic model of dynamic recrystallization was established.Analysis of rheological stress curve shows that with deformation of 6061 aluminum alloy at 350～500℃,the strain rate is decreased,so the structure of the 6061 alloy is more easily to undergo dynamic crystallization,and the stress softening phenomenon is more obvious.