(西北工業(yè)大學(xué) 材料學(xué)院，西安 710072)
摘 要: 在Gleeble−1500型熱模擬實(shí)驗(yàn)機(jī)上研究TA15(Ti-6Al-2Zr-1Mo-1V)鈦合金在溫度860~1 100 ℃、應(yīng)變速率0.001~10/s、變形程度15%~75%條件下的微觀組織演變規(guī)律。結(jié)果表明，該合金在溫度860~980 ℃范圍內(nèi)成形時(shí)，隨著溫度的升高，初生α相減少，動(dòng)態(tài)再結(jié)晶逐漸受到抑制；隨著應(yīng)變速率的降低，初生α晶粒略有增大。該合金在1 040~1 100 ℃范圍內(nèi)成形時(shí)，軟化機(jī)制主要為動(dòng)態(tài)回復(fù)，塑性成形后的組織由扁條狀β晶粒構(gòu)成，晶界處有少量呈鋸齒狀的再結(jié)晶晶粒。基于定量金相測(cè)量，建立了TA15鈦合金860~980 ℃高溫變形時(shí)初生α相體積分?jǐn)?shù)、晶粒尺寸以及再結(jié)晶分?jǐn)?shù)模型。將模型與有限元結(jié)合，對(duì)熱壓縮成形過程組織演化進(jìn)行了數(shù)值模擬。模型平均誤差小于13%，可以滿足預(yù)測(cè)需要。
關(guān)鍵字: TA15鈦合金；高溫變形；微觀組織；數(shù)值模擬
（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
