(西北工业大学 材料学院，西安 710072)
摘 要: 在Gleeble−1500型热模拟实验机上研究TA15(Ti-6Al-2Zr-1Mo-1V)钛合金在温度860~1 100 ℃、应变速率0.001~10/s、变形程度15%~75%条件下的微观组织演变规律。结果表明，该合金在温度860~980 ℃范围内成形时，随着温度的升高，初生α相减少，动态再结晶逐渐受到抑制；随着应变速率的降低，初生α晶粒略有增大。该合金在1 040~1 100 ℃范围内成形时，软化机制主要为动态回复，塑性成形后的组织由扁条状β晶粒构成，晶界处有少量呈锯齿状的再结晶晶粒。基于定量金相测量，建立了TA15钛合金860~980 ℃高温变形时初生α相体积分数、晶粒尺寸以及再结晶分数模型。将模型与有限元结合，对热压缩成形过程组织演化进行了数值模拟。模型平均误差小于13%，可以满足预测需要。
关键字: TA15钛合金；高温变形；微观组织；数值模拟
（College of Materials Science and Engineering, Northwestern Polytechniacal University, Xi'an 710072, China）
Abstract:Hot compressive deformation of TA15(Ti-6Al-2Zr-1Mo-1V) titanium alloy was carried out with the hot-simulation machine of Gleeble−1500 over the range of deformation temperature from 860 ℃ to 1 100 ℃, strain rate from 0.001/s to 10/s, deformation from 15% to 75%. The results reveal that the volume fraction of primary α decreases and the dynamic recrystallization is restrained along with increasing temperature, the primary α grain size increases a little along with increasing strain rate in the temperature range from 860 ℃ to 980 ℃. The main softening mechanism is dynamic recovery , the microstructure is flat β grain and there is a little dynamic grain of indention on the grain boundary from 1 040 ℃ to 1 100 ℃. The microstructure evolution model of primary α volume fraction, grain size and dynamic recrystallization fraction of TA15 titanium alloy in (α+β) field is established based on quantitative metallurgical technique. By combining the microstructure model with finite element method, the microstructure evolution is predicted during isothermal compressive deformation. The average error is smaller than 13% by comparing the results of simulation and experiment.
Key words: TA15 titanium alloy; hot compressive deformation; microstructure; numerical simulation
