(1. 中北大学 材料科学与工程学院，太原 030051；
2. 宝钛集团有限公司 科技部，宝鸡 721014)
摘 要: 在Gleeble−3800型热加工模拟实验机上，对BTi-62421S合金在变形程度70%、变形温度850~1 050 ℃、应变速率0.01~30 s−1范围内进行高温压缩实验。通过真应力—真应变曲线，分析流动应力随变形热力参数的变化规律。结果表明：BTi-62421S合金高温变形的流变应力随温度的升高和应变速率的降低而减小；随着应变的增大，合金的真应力—真应变曲线在经历了明显的加工硬化阶段后达到最大值，然后出现流变“软化”现象。以经典的双曲正弦形式模型为基础建立了BTi-62421S合金高温变形的本构方程，同时通过对数据回归处理计算了合金高温变形的应力指数n、应变激活能Q。
关键字: BTi-62421S；高温变形；流动应力；本构模型
of BTi-62421S alloy
（1. College of Materials Science and Engineering, North University of China, Taiyuan 030051, China;
2. Scientific and Technical Department, Baoti Group Co., Ltd., Baoji 721014, China）
Abstract:The high temperature compression tests of BTi-62421S titanium alloy were carried out in the temperature range of 850−1 050 ℃ and strain rate range of 0.01−30 s−1 using the Gleeble3800 thermal-mechanical simulator. The change of flow stress with deformation thermal parameters was revealed from true stress—true strain curves. The results show that the true stress of high temperature deformation of BTi-62421S alloy increases with the decrease of deformation temperature and the increase of strain rate. With the increase of true strain, due to the work hardening of the alloy, the true stress attains the peak, and then flow softening occurs. The constitutive equation for high temperature deformation of BTi-62421S alloy is obtained on the basis of hyperbolic sine form model, and the material constants, including activation energy Q and stress exponent n are also obtained.
Key words: BTi-62421S Ti alloy; high temperature deformation; flow stress; constitutive equation
