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在温度为525℃、应变速率为0.0008～0.032s-1条件下,采用等应变速率拉伸法研究了AA5083合金的流变行为,探讨了n、m值的测量方法,并建立了修正的粘塑性本构模型。结果表明:AA5083合金在该条件下流变应力随应变速率的升高而增加,表现应变速率硬化特征;各变形曲线呈现应变硬化、稳态变形及应变软化三阶段。应变硬化指数n随应变速率减小而增加,应变速率敏感性指数m随应变增加而减小,均为动态晶粒长大所致;合金应变软化表现为动态再结晶特征。模型预测值与实验值吻合良好。
The rheological behavior of AA5083 alloy was studied at constant strain rate of 0.0008 ~ 0.032s-1 at 525 ℃ and strain rate. The measuring methods of n and m were discussed, and the modified viscous Plastic constitutive model The results show that the rheological stress of AA5083 alloy increases with the increase of strain rate under this condition, which shows the characteristics of strain rate hardening. The deformation curves show the three stages of strain hardening, steady deformation and strain softening. The strain hardening index n increases with the decrease of strain rate, and the strain rate sensitivity index m decreases with the increase of strain, both of which are caused by dynamic grain growth. The strain softening behavior of alloy shows dynamic recrystallization. The model predicted value is in good agreement with the experimental data.