基于应变量耦合的低成本Ti-Al-V-Fe合金本构关系

为了获取新型低成本Ti-Al-V-Fe合金热成形工艺窗口,研究了热加工参数为变形温度875~1100℃、应变速率0.001~1 s^-1、变形量70%的低成本Ti-Al-V-Fe合金热变形行为。结果表明:流变应力与变形温度成反比,与应变速率成正比,合金为典型负温度、正应变敏感材料。以热模拟实验数据为依据,运用多元线性回归方法,确定了材料常数与应变的函数关系,建立了基于应变量耦合的α+β两相区及β单相区Arrhennius本构方程,其耦合系数为0.98,表明建立的模型在给定任意应变量时可准确预测流变应力。根据热激活能,判别合金在不同相区软化机制,单相区为动态回复,两相区为动态再结晶。

Constitutive relationship of low cost Ti-Al-V-Fe alloy based on strain coupling

In order to determine the optimal hot deformation process window of the new low-cost Ti-Al-V-Fe alloy,the hot deformation behavior was investigated with the deformation temperature of 875~1100℃,strain rate of 0.001~1 s^-1 and deformation of 70%.The results indicate that the alloy is a typical negative temperature and positive strain sensitive material,the flow stress is inversely proportional to the deformation temperature and positively proportional to the strain rate.Based on the experimental data of thermal simulation,the Arrhennius functional relation between material constant and strain was solved by a multiple linear regression method.The Arrhennius constitutive equations of α+β two-phase region and β single-phase region were put forward based on the strain coupling.The coupling correlation coefficient reaches 0.98,which indicates that the established model could accurately predict the flow stress when given any strain.The softening mechanism of the alloy in different phase zones is identified according to the thermal activation energy.The single-phase region is dynamic recovery,and the two-phase region is dynamic recrystallization.