基于应变补偿和修正项的新型铝锂合金温热变形本构模型

采用UTM5000电子万能拉伸试验机,在变形温度573~648K和应变速率0.001~0.1s-1条件下对2060-T8铝锂合金进行等温恒应变速率拉伸试验，得到其在变形过程中的真应力-真应变曲线，建立了基于应变补偿和修正项的温热变形本构方程。通过扫描电子显微镜(SEM)分析拉伸断口，对2060-T8铝锂合金的温热变形行为进行研究。结果表明：2060-T8铝锂合金对变形温度和应变速率具有较高的敏感性，流变应力曲线呈现出应变硬化和流变软化的特征，随着变形温度的升高和应变速率的降低，稳态流变特征逐渐消失，其在温热变形条件下的断裂形式为韧性断裂。修正的本构模型与实验值吻合度较高，可以为2060-T8铝锂合金温热变形的有限元模拟提供前提条件。

Constitutive Model of New Al-Li Alloy during Warm Deformation Considering Strain Compensation and Correction Term

Isothermal tensile tests of 2060-T8 Al-Li alloy were conducted on a UTM5000 electronic universal tensile testing machine at deformation temperature ranging from 573 to 648K and strain rate ranging from 0.001 to 0.1s-1. The true stress-strain curves of 2060-T8 Al-Li alloy were obtained and constitutive equation considering the strain compensation as well as correction term was also established. The warm deformation behavior of 2060-T8 Al-Li alloy was investigated by the analysis of tensile fractures using scanning electron microscopy (SEM). The results show that 2060-T8 Al-Li alloy is highly sensitive to deformation temperature and strain rate. The true stress-strain curves show the characteristics of strain hardening followed by flow softening and steady flow characteristic gradually disappears with the increase of deformation temperature and the decrease of strain rate. In addition, 2060-T8 Al-Li alloy is of ductile fracture during warm deformation. The modified constitutive model is in great agreement with the experimental data, which can provide a precondition for the finite element analysis of 2060-T8 Al-Li alloy during warm deformation.