考虑高温再结晶Ti-6Al-4V合金的修正J-C本构模型

Modified Johnson-Cook constitutive equation of Ti-6Al-4V alloy considering high temperature recrystallization

为了研究Ti-6Al-4V合金在高速切削下的真实流动应力-应变关系,针对当温度达到临界变化温度时,材料的流动应力会突然下降这一现象,建立了一种修正Johnson-Cook(J-C)本构方程。修正的J-C本构关系能够准确地描述加工温度范围内再结晶软化机制对材料流动应力的影响,预测结果与试验数据吻合良好,特别是在高温阶段,流动应力计算值与试验值误差在4%以内,正确地反映了Ti-6Al-4V合金各个温度下的真实流动应力变化。结果表明,修正后的J-C本构方程可以用于研究分析Ti-6Al-4V合金的流动应力特征与规律。

In order to study the true flow stress-strain relationship of Ti-6Al-4V alloy under high speed cutting,a modified Johnson-Cook（J-C） constitutive equation was proposed which considering the phenomenon that the flow stress of this material will suddenly drop when the temperature reaches a critical change.The results show that the modified constitutive equation can accurately describe the effect of recrystallization softening mechanism on the material flow stress in the sensitive temperature range.The predicted flow stress values of modified J-C constitutive have an agreement with the experimental data,especially in high temperature stage.The error between the calculated flow stress and the experiment data is within 4%,it shows that this modified constitutive equation can be used to research the characteristics and regulations of flow stress for Ti-6Al-4V alloy.