Ti-22Al-26Nb合金热变形本构方程建立及软化行为研究

Establishment of Constitutive Equation and Research on Softening Behavior of Ti-22Al-26Nb Alloy during Hot Deformation

摘要:

作为最具潜力的航空航天高温结构材料，Ti2AlNb基合金具有高的比强度和良好的高温蠕变性能。本文对热轧态Ti-22Al-26Nb合金高温变形中的力学行为和再结晶行为进行研究，建立其高温本构关系模型，对其中呈现出的动态再结晶多应力峰值曲线特征（以1000℃，0.1s-1为例）进行拟合分析。结果表明：基于双曲正弦函数建立Ti-22Al-26Nb合金的高温本构关系模型的精度较高，最大误差为2.6%，可以很好地描述合金在高温变形时各热力学参数之间高度非线性的复杂关系，由修正的Avrami方程预测得知再结晶体积分数与应变呈现典型的再结晶动力学增长趋势，揭示了该合金高温变形过程中复杂的软化行为。

Abstract:

As the most promising aerospace high temperature structural materials, Ti2AlNb alloys have high specific strength and good high temperature creep properties. The high temperature mechanical behavior and recrystallization behavior of Ti-22Al-26Nb alloy were studied. A high temperature constitutive model of the alloy was established .The dynamic recrystallization multi-stress peak curve was analyzed by fitting the experimental results. The results show that it is feasible to establish the high temperature constitutive model of Ti-22Al-26Nb alloy based on the hyperbolic sine function, which can describe the high nonlinearity of the thermodynamic parameters of Ti-22Al-26Nb alloy at high temperature complex relationship, the maximum error is 2.6%. From the modified Avrami equation, it is predicted that the recrystallization volume fraction and the strain show a recrystallization kinetics growth trend, and the complex softening behavior of the alloy during high temperature deformation is revealed.