5A90铝锂合金热态下本构关系研究

进行了5A90铝锂合金在200℃~450℃温度范围和0.3×10-3s-1~0.2×10-1s-1应变速率范围内的单向拉伸试验。结果表明,5A90铝锂合金的流动应力随变形温度的升高而减小,随应变速率的增大而增大;而其最大延伸率的变化趋势与流动应力的相反;最佳的成形温度范围在400℃左右。通过试验数据的计算及拟合,得到了任意温度下5A90铝锂合金应力-应变-应变速率关系的本构方程。

Research on the constitutive relationship of 5A90 Aluminum-lithium alloy at hot forming temperature

Uniaxial tensile test of 5A90 Al-Li alloy sheet is investigated at the temperature range of 200℃~450℃ and the strain rate range of 0.3×10-3s-1~0.2×10-1s-1.It is shown that the flow stress of 5A90 Al-Li alloy in uniaxial tension decreases as the deformation temperature increases,and the flow stress increases as the strain rate increases,however,the tendency of total elongation is just the reverse,and the optimum forming temperature is 400℃.The constitutive equation of stress,strain and stain rate for 5A90 Al-Li alloy at any temperature is obtained by fitting the experimental data,which provides flow stress model for FEM simulation of hot forming.