铸态TC21钛合金高温变形行为研究
Study on High Temperature Deformation of TC21 Alloy Ingot
冯 菲1, 曾卫东1, 朱艳春1, 赵永庆2
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作者单位：(1. 西北工业大学 材料学院 凝固技术国家重点实验室, 陕西 西安 71007; 2. 西北有色金属研究院, 陕西 西安 710016)
中文关键字：TC21钛合金； 铸锭； 高温变形； 变形机制； 本构方程
英文关键字：TC21 titanium alloy; ingot; hot deformation; deforming mechanism; constitutive equation
中文摘要：以铸态TC21钛合金为研究对象，在Gleeble3500热模拟试验机上对TC21钛合金在开坯温度1000～1150 ℃、应变速率0.01～10 s-1的高温变形行为进行了研究。结果表明，铸态TC21钛合金流动应力随应变速率的提高和温度的降低而升高，具有温度和应变速率敏感性；β区变形激活能为196.277 kJ/mol，变形机制以动态回复为主；低应变速率下(■≤0.1 s-1)，流变曲线呈稳态流动特征，拉长的β晶粒晶界呈锯齿状，晶界处发生连续再结晶；高应变速率下(■ ≥1 s-1)，拉长的β晶粒晶界平直，为典型动态回复；高应变速率且温度相对较低(■=10 s-1，T≤1150 ℃)时，流变曲线呈流动软化特征，原因是局部温升效应及局部塑性流动。
英文摘要：TC21 titanium alloy ingot was compressed in β phase region on a Gleeble 3500 simulator at 1000 ℃～1150 ℃ and strain rate range of 0.01～10 s-1. The experimental results show that the flow stress of TC21 alloy increases with the decrease of temperature and the increase of strain rate, and this alloy is also sensitive to temperature and strain rate. The deformation activation energy is 196.277 kJ/mol in β phase, and the main deformation mechanism of TC21 titanium alloy is dynamic recovery. At lower strain rate(■≤0.1 s-1), flow curves tend to steady-state flow phenomena, however, a typical continuous recrystallization with serrated grain boundaries occurs. At higher strain rate(■≥1 s-1), grain boundary represents sliding, which is typical dynamic recovery. At lower temperature and higher strain rate(■=10 s-1, T≤1150 ℃), the curves tend to yield, which is attributed to flow localization.