(1. 西安建筑科技大学 冶金工程学院，西安 710055；2. 武汉钢铁股份有限公司，武汉 430080)
摘 要: 在Gleeble−1500热模拟机上对120°模具室温Bc方式ECAP变形8道次制备的平均晶粒尺寸约为200 nm的工业纯钛进行等温变速压缩实验，研究超细晶工业纯钛在变形温度为298~673 K和应变速率为1×10−4~1×100 s−1条件下的流变应力行为。结果表明：变形温度和应变速率均对流变应力具有显著影响，峰值应力随变形温度的升高和应变速率的降低而降低；流变应力在变形初期随应变的增加而增大，出现峰值后逐渐趋于平稳，呈现稳态流变特征。采用双曲正弦模型确定了超细晶工业纯钛的变形激活能Q=104.46 kJ/mol和应力指数n=23，建立了相应的变形本构关系。
关键字: 超细晶工业纯钛；热压缩变形；流变应力；本构关系；变形激活能
（1. School of Metallurgical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China;
2. Wuhan Iron and Steel Company Limited, Wuhan 430080, China）
Abstract:The hot compression deformation behavior of ultrafine-grained (UFG) commercially pure (CP) Ti with the average grain size of about 200 nm was studied by isothermal simulation tests at the deformation temperature of 298− 673 K and the strain rate of 1×10−4−1×100 s−1 on the Gleeble−1500 thermal-mechanical simulator. UFG CP-Ti was produced by ECAP up to 8 passes with a die of 120° using route Bc at room temperature. The results show that the deformation temperature and strain rate greatly affect the flow stress. The peak stress decreases with increasing deformation temperature and decreasing strain rate. The flow stress increases with increasing strain and tends to be constant after a peak value which is the characteristic of the steady flow state. The deformation activation energy and stress exponent were obtained using the hyperbolic-sine mathematics model to be Q=104.46 kJ/mol and n=23, and the hot deformation constitutive relationship was established.
Key words: ultrafine-grained commercially pure (CP)-Ti; hot compression deformation; flow stress; constitutive relationship; deformation activation energy
