2060-T8E30铝锂合金的高温拉伸变形行为及显微组织研究

High Temperature Tensile Deformation Behavior and Microstructure of 2060-T8E30 Al-Li Alloy

利用Sans CMT4104型拉伸试验机、光学显微镜、电子显微镜研究变形温度、应变速率对2060铝锂合金热变形行为与显微组织的影响,分析合金在不同热变形条件下的真应力-真应变曲线,并结合Zener-Hollomon方程得到合金的热变形参数。通过对合金第二相、空洞、断口形貌的观察,研究了合金热拉伸显微组织的演变规律。结果表明:高温拉伸时合金的峰值应力随变形温度的升高和应变速率的减小而下降。合金的延伸率随变形温度的升高而提高,随应变速率的减小先提高后降低,在500℃/0.01 s^(-1)条件下延伸率最佳,达到170%。通过计算,得到合金的变形激活能为227.28 kJ/mol。显微组织显示,随着变形温度的升高和应变速率的减小,空洞的数量增多、尺寸增大;在变形温度为475~500℃时,合金析出了第二相并发生了几何动态再结晶。

The effect of deformation temperature and strain rate on the microstructure and hot deformation behavior of 2060-T8E30 Al-Li alloy was stu-died by Sans CMT4104 tensile testing machine,optical microscopy(OM)and scanning electron microscope(SEM).The true stress-strain curves of the alloy under different thermal deformation conditions were analyzed,and the thermal deformation parameters of the alloy were obtained by combining the Zener-Hollomon equation.By observing the second phase,cavity and fracture morphology,the microstructure evolution of the alloy under hot stretching was studied.The results show that the peak stress of the alloy decreases with the increase of deformation temperature and the decrease of strain rate.The elongation of the alloy increases with the increase of deformation temperature and then decreases with the decrease of strain rate.The elongation reaches 170%at 500℃/0.01 s^(-1).The deformation activation energy of the alloy is 227.28 kJ/mol.The microstructure shows that the number and size of cavities increase with the increase of deformation temperature and the decrease of strain rate.When the deformation temperature is 475—500℃,the second phase is precipitated and the geometric dynamic recrystallization occurs.