热变形条件对含钪铝锂合金流变应力和显微组织的影响

Effects of Hot Deformation Conditions on Flow Stress and Microstructure of Al-Li Alloy Sc-containing

在变形温度为380～500℃,应变速率为0.001～10 s-1的条件下,采用Gleeble-1500热模拟试验机对含钪Al-Cu-Li-Zr合金的热变形行为进行了研究。结果表明:含钪Al-Cu-Li-Zr合金流变应力随变形温度升高和应变速率的降低而减小;变形初期,应力值随应变的增加迅速提高,显示出明显的加工硬化效应。当应力值达到峰值后,随着变形增加,流变应力逐步降低,合金出现明显的软化现象。根据流变应力本构方程及利用作图法和线性回归方法求解得出各参数值,得出流变峰值应力方程;该合金在高温压缩试验中会发生动态回复,在一定条件下会发生动态再结晶,并且温度越高应变速率越低,该合金越易发生动态再结晶,从而表现出其流变应力越低。

Compressive deformation behavior of Al-Cu-Li-Zr alloy containing scandium was investigated at the temperature from 380 ℃ to 500 ℃ and strain rates from 0.001 s-1 to 1 s-1 by Gleeb-1500 thermal simulator.The results show that flow stress of Al-Cu-Li-Zr alloy containing scandium decreases with the increase of deformation temperature and the decrease of strain rate.At the initial deformation,the stress values increase rapidly with the increase of strain,Al-Cu-Li-Zr alloy containing scandium shows apparent work-hardening effect.At peak stress,with the increase of deformation,the flow stress gradually reduces and the alloy is softened noticeably.Some parameters and peak flow stress equations were derived via mapping method and linear regression.The alloy shows the steady-state flow characteristics during hot compression test.And under certain conditions,dynamic recrystallization occurs in the alloy.The lower the strain rate,the easier the recrystallization occurs by merging and growth of sub-grain.Thus the alloy shows a lower flow stress.