Ti60合金保温过程中片状组织的粗化行为  

Coarsening Behavior of Lamellar Microstructure of Ti60 Alloy during Heat Treatment

作　　者：李冬[1] 曾卫东[1] 李欣 高雄雄 徐建伟[1] Li Dong;Zeng Weidong;Li Xin;Gao Xiongxiong;Xu Jianwei(State Key Laboratory of Solidification Processing,Defense Technologies Innovation Center of Precision Forging and Ring Rolling,School of Materials Science and Engineering,Northwest Polytechnical University,Xi'an 710072,China)

机构地区：[1]西北工业大学材料学院凝固技术国家重点实验室国防科技工业精密锻造与环轧技术创新中心,陕西西安710072

出　　处：《稀有金属》2022年第3期273-280,共8页Chinese Journal of Rare Metals

基　　金：国家重点研发计划项目(2016YFB0301203)资助。

摘　　要：研究了Ti60合金在α+β两相区(965℃)不同保温时间下加热过程中片状组织演变及粗化行为。利用X射线衍射(XRD)分析了相成分,用扫描电子显微镜(SEM)观察了保温后片层的显微组织,用能谱仪(EDS)分析了析出颗粒物的元素成分。结果表明:Ti60合金在两相区保温过程中,在不同的保温时间下,α/β相界面均不再光滑,β相出现分支结构。Ti60合金在β退火处理后经炉冷析出大量颗粒物,这些颗粒物随着保温时间的增加,逐渐溶解。保温过程中片状α相和片状β相的厚度均有所增加,当保温时间较短时,片层厚度增速较快,随着保温时间的增加,片层厚度增速降低,片层厚度最终趋于平稳。在保温过程中β相出现的分支结构使α/β相间形成曲率差,为溶质原子的迁移提供了驱动力,从而使α相和β相的片层厚度连续增长。此外,Ti60合金炉冷过程中析出的颗粒物为硅化物,主要分布在β晶界及其内部,多呈球状或棒状。Due to its high thermal strength,oxidation resistance and good creep resistance,Ti60 alloy,as a multi-element reinforced near-alpha high-temperature titanium alloy with independent intellectual property rights designed and developed by China,had been widely studied in terms of its processing technology,microstructure and mechanical performance.The coarsening of the lamellar structure of titanium alloy often occurred during solid solution or high-temperature aging,which affected the ratio of the equiaxed microstructure and the lamellar microstructure,and ultimately had a significant impact on the mechanical properties of the parts.Therefore,it was essential to systematically study the coarsening behavior of the lamellar structure of Ti60 alloy during heat treatment.The microstructure evolution and coarsening behavior of the lamellar structure in Ti60 titanium alloy heat treated atα+βtwo-phase(965℃)with different holding time were investigated.The phase structures of as-received Ti60 alloy,the microstructures of lamellae after heat treatment,and chemical composition of particle/rod-shaped precipitates were analyzed by X-ray diffraction(XRD),optical microscope(OM),scanning electron microscope(SEM)and energy dispersive spectrometer(EDS),respectively.The thickness of the lamellae was measured by using SEM processed with Image-Pro Plus software,and quantitative analysis was performed using the parallel equally spaced raster line truncation method.In addition,the coarsening mechanism ofβphase of Ti60 alloy during heat treatment was also explored.The results showed that afterβannealing treatment and furnace cooling,a large number of particles precipitated in Ti60 alloy.During heated atα+βtwo-phase region,the morphology of lamellarα/βphase interface was no longer smooth andβphase appeared the branch structure with different holding time.The particles which precipitated in Ti60 alloy after furnace cooling gradually dissolved with increasing holding time.Moreover,the lamellarαandβphases gradually became thicker

关 键 词：Ti60合金 片状组织 粗化行为 析出物 

分 类 号：TG166.5[金属学及工艺—热处理]