TC17钛合金热流变行为及组织演变机制研究  

Thermal Flow Behaviors and Microstructure Evolution of TC17 Alloy

作　　者：韩言 赵飞 万明攀[1] 黄朝文 刘源 李昌民 Han Yan;Zhao Fei;Wan Mingpan;Huang Chaowen;Liu Yuan;Li Changmin(Guizhou Key Laboratory of Materials Strength and Structure,School of Materials Science and Metallurgical Engineering,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学材料科学与冶金工程学院贵州省材料结构与强度重点实验室,贵州贵阳550025

出　　处：《稀有金属》2020年第3期234-241,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51461008,51571066);贵州省科技计划项目(黔科合支撑[2017]2313);黔科合平台人才项目([2016]5654,[2016]5621)资助。

摘　　要：利用热模拟机对TC17钛合金进行等温压缩试验,变形温度范围为770~950℃,应变速率范围为1×10^-2~1×10^1 s^-1,研究具有片状初始α相组织的TC17合金在α+β两相区和β单相区热变形行为。结果表明,TC17合金有两种不同的流变软化现象,在α+β两相区,高应变速率以及低应变速率下变形时均出现持续软化行为;在β单相区,流变应力达到峰值后迅速降低到一个稳定值,在高应变速率下表现出明显的不连续屈服现象,随后出现振荡,而在低应变速率下真应变对流变应力的影响很小,表现出稳定的流变行为;用Arrhenius正弦方程构建流变应力与变形温度、应变速率的关系,发现α+β两相区的形变激活能随应变的增加从670.1 kJ·mol^-1下降到370.1 kJ·mol^-1,在β单相区,随着应变的增加,形变激活能从301.4 kJ·mol^-1下降到239.3 kJ·mol^-1;TC17合金在α+β两相区的变形机制都是动态再结晶(球化),在β单相区变形时,高应变速率下的主要变形机制是动态回复,而低应变速率下为β相动态再结晶。Hot deformation behavior of TC17 alloy with an initial lamellar microstructure in the α+β and β phase field was investigated at the temperatures of 770~950℃and the strain rates of 1×10^-2~1×10^1 s^-1.The research showed that TC17 alloy had two different flow softening phenomena,in the α+β phase region,continuous softening could be observed at both high strain rates and low strain rates.In the β phase region,flow stress reached steady state following the flow oscillations at high strain rates,and the strain affected slightly the flow stress in low strain rate,showing a steady flow behavior.A hyperbolic-sine Arrhenius-type equation was used to characterize the dependence of the flow stress on defonnation temperature and strain rate.The activation energy of deformation in the α+βphase field decreased from 670.1 to 370.1 kJ·mol^-1 with increasing strain,while it decreased from 301.4 to 239.3 kJ·mol^-1 in the single β phase field.The deformation mechanism of TC17 alloy in the two-phase region was dynamic recrystallization(globularization).The main deformation mechanism was dynamic recovery at high strain rate in the single-phase region,and the recrystallization of the beta phase occured at low strain rate.

关 键 词：TC17钛合金 热变形行为 动力学 微观结构 

分 类 号：TG146[一般工业技术—材料科学与工程]