加工硬化率法研究Ti-10V-2Al-3Fe合金β区变形动态再结晶的临界条件

Critical conditions of dynamic recrystallization in β region deformation of Ti-10V-2Al-3Fe alloy using working hardening rate method

采用Thermecmaster-Z型热/力模拟试验机在变形温度为825～1125℃,应变速率为0.001～1 s^(-1)条件下对Ti-10V-2Al-3Fe合金进行热模拟压缩实验,分析了热变形参数对其流变行为的影响,并通过加工硬化率方法研究了该合金的动态再结晶临界条件。结果表明:合金的流变应力随变形温度的降低或应变速率的提高而增大;通过lnθ～ε曲线出现拐点及dlnθ/dε～ε曲线出现最小值判据,确定了该合金的动态再结晶临界应变;动态再结晶临界应变随应变速率的增大及变形温度的降低而增加;Z参数方程能较好地反映合金动态再结晶临界应变与热变形条件间的关系,动态再结晶临界应变与Z参数间的关系可表示为ε_c=2.6735×10^(-2)Z^(0.0817);临界应变与峰值应变之间存在线性关系,即ε_c=0.508ε_p。

The hot compression experiments of Ti-10 V-2 Al-3 Fe alloy were carried out under deformation temperature of 825-1125 ℃ and strain rate of 0.001-1 s-1 with a Thermecmaster-Z thermal/force simulator. The effect of hot deformation parameters on flow behavior of the alloy was analyzed. The critical condition of dynamic recrystallization(DRX) of the alloy was studied by the method of work hardening rate. The results show that the flow stress of the alloy increases with the decrease of deformation temperature or the increase of strain rate, and the critical strain of dynamic recrystallization is determined by the inflection point of lnθ-ε curve and the minimum criterion of dlnθ/dε-ε curve. The critical strain of dynamic recrystallization increases with the increase of strain rate and the decrease of deformation temperature. The Z parameter equation can better reflect the relationship between the critical strain of dynamic recrystallization and the hot deformation condition, and the relation between the critical strain of dynamic recrystallization and the Z parameter can be expressed as εc=2.6735×10-2Z0.0817, and there is a linear relationship between the critical strain and the peak strain, that is, εc=0.508εp.