铝合金2219-O热拉伸流变行为研究

Thermal tensile rheological behavior of aluminum alloy 2219-O

通过热拉伸实验,研究了在变形温度473-673 K、应变率0.001-0.1 s^（-1）条件下铝合金2219-O流变应力的变化规律,并建立材料本构关系。实验结果表明：在所研究的温度和应变率范围内,铝合金2219-O流变应力受到加工硬化和动态回复软化机制的综合影响,随着温度的升高,两种机制逐渐达到平衡状态。该材料属于正应变率敏感材料,流变应力随应变率的增加而增大,随温度的增加而降低。基于Hollomen模型,通过考虑应变、应变率和温度之间的耦合效应,建立了中高温下铝合金2219-O材料本构模型。流变应力的预测值与实验值对比表明该模型能够准确地反映铝合金2219-O热拉伸流变行为。

Thermal tensile tests were conducted to study the flow stress variation law of 2219-O sheet under the condition that the deformation temperature of 473-673 K and the strain rate of 0. 001-0. 1 s^（-1）,and the constitutive relationship of the material was built. The experimental results show that the flow stress of 2219-O is affected by mechanical hardening mechanism and dynamic recovery softening mechanism in the studied temperature and strain rate range,and the two mechanisms approach to balance with the increase of temperature. The material is positive strain rate sensitive,and the flow stress increases with the increase of strain rate and decreases with the increase of temperature. Based on Hollomen model,a constitutive model for 2219-O under medium and high temperature was established considering the coupling effect of strain,strain rate and temperature. According to the comparison of the predicted flow stress values and experimental ones,the constitutive model can accurately reflect the thermal tensile rheological behavior of 2219-O.