TC21钛合金线性摩擦焊接头组织特征研究  

Microstructure Characteristics of TC21 Titanium Alloy Linear Friction Welded Joint

作　　者：冯朝瑞 马铁军 李菊 李文亚 FENG Zhaorui;MA Tiejun;LI Ju;LI Wenya(Key Laboratory of Friction Welding Engineering Technology of Shaanxi Province,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China;Aeronautical Key Laboratory for Welding and Joining Technologies,AVIC Manufacturing Technology Institute,Beijing 100024,China)

机构地区：[1]西北工业大学材料学院陕西省摩擦焊接工程技术重点实验室,陕西西安710072 [2]中国航空制造技术研究院航空焊接与连接技术航空科技重点实验室,北京100024

出　　处：《热加工工艺》2023年第21期73-76,共4页Hot Working Technology

基　　金：国防基础科研计划项目(JCKY2018205B026)。

摘　　要：选用TC21损伤容限型钛合金开展了线性摩擦焊接(LFW)试验研究。利用光学显微镜和扫描电镜观察并分析了接头组织特征与形成机制,利用显微硬度计测试了接头的显微硬度分布。结果表明,TC21钛合金因网篮组织抗变形能力较高,形成与双态钛合金差异较大的LFW接头组织。热力影响区(TMAZ)宽度很窄,约450μm,仅在近焊缝(WZ)区域的TMAZ,棒状α沿摩擦方向被拉长变形呈现流线形貌,且形成明显的热影响区(HAZ)。HAZ受热影响发生次生α分解;TMAZ受梯度热-力影响发生不同程度变形,次生α分解,二次α逐渐析出并长大;WZ发生了动态再结晶形成细晶,晶内析出大量针状α’及细小二次α。从BM→HAZ→TMAZ→WZ,显微硬度值先降低后升高,整体接头呈“W”形分布。The linear friction welding(LFW)test of TC21 damage-tolerant titanium alloy was carried out.The microstructure characteristics and formation mechanism of the joint were analyzed by using an optical microscope and a scanning electron microscope,the microhardness distribution of the joint was tested by using a microhardness tester.The results show that the TC21 titanium alloy has a high resistance to deformation due to its basketweave microstructure,and a special joint microstructure is formed,which is quite different from that of the LFW joint of duplex titanium alloys.The width of thermo-mechanically affected zone(TMAZ)is very narrow,about 450μm,and the TMAZ near the weld zone(WZ)has elongated rodαalong the friction direction,showing a streamlined appearance.In addition,an obvious heat-affected zone(HAZ)is formed,in which the primary secondaryαis decomposed under the thermal effect.The microstructure of TMAZ is deformed to varying degrees due to the gradient heat-force,the primary secondaryαis decomposed,and the secondaryαgradually precipitates and grows.The dynamic recrystallization has occurred in WZ and fine recrystallized grains are formed,and a large amount of needleα'and fine secondaryαare precipitated in recrystallized grains.From BM,HAZ,TMAZ to WZ,the microhardness decreases firstly and then increases,the joint overall shows a"W"shaped distribution.

关 键 词：TC21钛合金 线性摩擦焊 组织 显微硬度 

分 类 号：TG456.9[金属学及工艺—焊接] TG453.9