(1. 南昌航空大學 材料科學與工程學院，南昌 330063；
2. 南京航空航天大學 材料科學與技術學院，南京 210016；
3. 北京航空材料研究院 鈦合金研究室，北京100095)
摘 要: 采用Thermecmaster-Z熱模擬試驗機在變形溫度1 050~1 100 ℃，應變速率10−3~1 s−1的條件下進行熱模擬壓縮試驗。采用加工硬化率處理方法對應力－應變數(shù)據(jù)進行處理，結合ln θ —ε曲線的拐點及−∂(ln θ)/∂ε —ε曲線最小值的判據(jù)，研究TA15鈦合金β區(qū)變形時的動態(tài)再結晶臨界條件。結果表明：在本實驗條件下，TA15鈦合金的ln θ —ε曲線均出現(xiàn)拐點及−∂(ln θ)/∂ε —ε曲線均出現(xiàn)最小值；臨界應變隨應變速率的增大及變形溫度的降低而增加，且臨界應變與峰值應變之間基本保持恒定值εc/εp=0.62；臨界應變預測模型函數(shù)關系可以表示為εc= 0.92×10−2Z 0.0843。
關鍵字: 加工硬化率；動態(tài)再結晶；臨界條件；TA15鈦合金
during deformation of β area in TA15 titanium alloy
（1. School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China;
2. College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
3. Titanium Alloys Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract:The hot simulation compression tests of titanium alloy TA15 were conducted at deformation temperature of 1 050−1 100 ℃ and strain rate of 10−3−1 s−1 with the Thermecmaster-Z hot simulation test machine. The critical conditions of dynamic recrystallization for onset of DRX during deformation of β area were obtained by computation of the work hardening rate θ from initial stress—stain data and introduction of the inflection point criterion of lnθ —ε curves and the minimum value criterion of −∂(lnθ)/∂ε —ε curves. The results indicate that an inflection point in the ln θ —ε curve appears and a minimum value of −∂(lnθ)/∂ε —ε curve is presented when the critical state is attained for this alloy. The critical strain increases with increasing the strain rate and decreasing the deformation temperature. There is linear relationship between critical strain and peak strain, i.e. εc/εp=0.65. The predicting model of critical strain is described by the function of εc=0.92×10−2Z0.0843.
Key words: work hardening rate; dynamic recrystallization; critical condition; TA15 titanium alloy
