Ti-22Al-25Nb合金板材高温拉伸变形行为的本构模型

Constitutive Models for Tensile Deformation Behavior of Ti-22Al-25Nb Alloy Sheet at Elevated Temperatures

摘要:

在1203~1283 K的温度范围内，以20 K的温度间隔对O相Ti-22Al-25Nb合金进行了等温单向拉伸试验，应变速率为2.5×10^-4、5.0×10^-4、1×10^-3、2×10^-3、4×10^-3、1×10^-2和5×10^-2 s^-1，并对不同变形温度下的试样组织进行了表征。通过实验结果，确定了本构模型的材料常数；α₂+B2/β+O三相区（1203~1243 K）和α₂+B2两相区（1243~1283 K）的拉伸变形激活能分别为845 165和412 779 J/mol。构建了Arrhenius本构模型来描述Ti-22Al-25Nb合金在不同温度下的拉伸变形行为。

Abstract:

Isothermal uniaxial tension tests for O phase-based Ti-22Al-25Nb alloys were conducted at 1203–1283 K with temperature interval of 20 K. The strain rates were 2.5×10^-4, 5.0×10^-4, 1×10^-3, 2×10^-3, 4×10^-3, 1×10^-2, and 5×10^-2 s^-1. The microstructures of specimens at different deformation temperatures were characterized. Through the experiment results, the material constants for the constitutive models are determined and the tensile deformation activation energies are 845 165 and 412 779 J/mol at α₂+B2/β+O three-phase region (1203–1243 K) and α₂+B2 two-phase region (1243–1283 K), respectively. Arrhenius-type constitutive models are constructed to characterize the tensile deformation behavior of Ti-22Al-25Nb alloy at different temperatures.