7A09半连续铸造铝合金的热模拟研究

Thermal Simulation Study of 7A09 Semi-continuous Casting Aluminum Alloy

对7A09半连续铸造铝合金进行了热模拟试验,研究了该合金在300、350、400℃,应变速率0.01、0.1、1、5 s^(-1),变形量50%条件下的流变行为。结果表明:该合金在变形温度300℃并且应变速率0.01 s^(-1)时具有明显的峰值应力,应力-应变曲线具有加工硬化、应变软化和稳态流变三个阶段;变形温度达到400℃时,曲线无明显峰值应力。通过计算求得应力水平参数α、应力指数n、变形激活能Q和结构因子A的具体值。应变速率和变形温度对于合金流变应力的影响可用Arrhenius方程和包含Zener-Hollomom参数的关系式表示。热加工图表明该合金具有较低的能量耗散率,高温变形的主要软化机制为动态回复。

The thermal simulation test of 7A09 semi-continuous casting aluminum alloy was carried out, the flow behavior of the alloy was studied at 300, 350 and 400℃, strain rate of 0.01,0.1,1 and 5 s^-1, and deformation of 50%. The results indicate that when the deformation temperature is 300℃ and the sWain rate is 0.01^ s-1, the alloy have obvious peak stress and the stress-strain curve has three stages： work hardening, sWain softening and steady state flow; when the deformation temperature reaches 400℃, there is no obvious peak stress in the curve. The specific values of the stress level parameter a, the stress exponent n, the deformation activation energy Q and the structural factor A are obtained by the calculation. The effects of strain rate and deformation temperature on the flow stress of the alloy can be expressed by the Arrhenius equation and the Zener-Hollomom parameter. The hot processing map shows that the alloy has lower energy dissipation rate, and the main softening mechanism of high temperature deformation is dynamic recovery.