摘要
目的定量分析不同热变形参数下片层α相的演化行为,探究不同热变形参数对TC21钛合金中片层α相动态球化行为的影响规律,并探讨片层α相在动态球化过程中的组织演变机理。方法基于Thermecmastor-z热模拟试验机对TC21钛合金开展不同变形参数的热压缩试验,结合SEM-EBSD材料表征技术进行显微组织的表征。结果随着温度从890℃升高至950℃,片层α相的平均厚度从0.65μm先增大至0.72μm后减小至0.16μm;在高温、低应变速率的条件下,片层α相球化百分数约为59%,而在低温、高应变速率条件下,片层α相球化百分数降至约26%;随着应变速率由0.001 s^(-1)升至1 s^(-1),片层α相球化百分数的增量由10%减少至不足2%。结论温度的高低主导了片层α相尺寸的变化趋势;变形温度的升高及应变速率的降低加速了片层α相的球化进程,而应变速率为主要影响因素;在α+β两相区变形过程中,LAGBs常形成于片层α相内部位错塞积程度较高的区域,并以此作为发生动态球化的界面。随着动态球化百分数的增大,α相中LAGBs的体积分数减小,而HAGBs的体积分数增大。
The work aims to quantitatively analyze the evolution behavior of lamellarαphase under different thermal deformation parameters,explore the effect law of different thermal deformation parameters on the dynamic globularization behavior of lamellarαphase in TC21 titanium alloy,and discuss the microstructure evolution mechanism of lamellarαphase during dynamic globularization.Hot compression tests of TC21 titanium alloy with different deformation parameters were carried out based on Thermecmastor-z thermal simulator,and the microstructure was characterized by SEM-EBSD material characterization technology.The results showed that with the increase of temperature from 890°C to 950°C,the average thickness of lamellarαphase increased from 0.65μm to 0.72μm and then decreased to 0.16μm.At high temperature and low strain rate,the percentage of lamellarαphase globularization was about 59%,while at low temperature and high strain rate,the percentage of lamellarαphase globularization decreased to about 26%.As the strain rate increased from 0.001 s^(-1)to 1 s^(-1)5,the increment of globularization percentage of lamellarαphase decreased from 10%to less than 2%.The temperature dominates the variation trend of lamellarαphase size;the increase of deformation temperature and the decrease of strain rate accelerate the globularization process of lamellarαphase,and the strain rate is the main influencing factor.In the deformation process ofα+βdual-phase region,LAGBs are often formed in the region with high dislocation pile-up in the lamellarαphase,and serve as the interface for dynamic globularization.With the increase of dynamic globularization percentage,the volume fraction of LAGBs inαphase decreases and the volume fraction of HAGBs increases.
作者
左正
邹俊杰
蒋佳君
董月
刘鑫刚
ZUO Zheng;ZOU Jun-jie;JIANG Jia-jun;DONG Yue;LIU Xin-gang(Deyang Wanhang Die Forging LLC,China National Erzhong Group Co.,Ltd.,Sichuan Deyang 618000,China;College of Mechanical Engineering,Yanshan University,Hebei Qinhuangdao 066004,China)
出处
《精密成形工程》
北大核心
2023年第2期60-67,共8页
Journal of Netshape Forming Engineering
关键词
TC21钛合金
热变形
片层α相
动态球化
球化机理
TC21 titanium alloy
hot deformation
lamellarαphase
dynamic globularization
globularization mechanism
