高氧TC4/TC17线性摩擦焊接头组织与显微硬度研究  

Microstructure and Microhardness of Linear Friction Welding Joint of High Oxygen TC4 and TC17

作　　者：李赞 张田仓[1] 李菊[1] 季亚娟[1] LI Zan;ZHANG Tiancang;LI Ju;JI Yajuan(Aeronautical Key Laboratory for Welding and Joining Technologies,AVIC Beijing Aeronautical Manufacturing Technology Research Institute,Beijing 100024 China)

机构地区：[1]北京航空制造工程研究所航空焊接与连接技术航空科技重点实验室

出　　处：《热加工工艺》2018年第13期37-40,44,共5页Hot Working Technology

摘　　要：对高氧TC4和TC17钛合金进行了线性摩擦焊试验,利用光学显微镜与扫描电镜对焊接接头的微观组织进行了分析,并研究了热处理对接头组织及显微硬度的影响。结果表明,焊态下高氧TC4侧焊缝比TC17侧窄,焊缝界面处生成共生晶粒,界面两侧发生动态再结晶。高氧TC4侧,靠近焊缝边缘的部分热力影响区形成大量的亚晶粒,部分区域发生动态再结晶形成细小的等轴β晶粒,冷却后晶粒内析出马氏体α＇相。TC17侧,β晶粒以及α晶界被拉长形成变形带,在靠近焊缝处、形成许多细小的等轴β晶粒。经过焊后热处理,高氧TC4的TMAZ亚稳态马氏体α＇相分解,高度变形的β相中析出片层状α相;TC17侧TMAZ组织为细小的针状α相。焊缝中心的共生晶粒组织不均匀,由相互交错的大小α片层组成。焊态下焊缝中心硬度最高;热处理后,TC17侧焊缝及热力影响区硬度大幅度增加。The linear friction welding experiment of the high oxygen TC4 and TC 17 titanium alloys was carried out. The microstructure of the welded joint was analyzed by means of optical microscopy and scanning electron microscopy, and the effect of heat treatment on the microstructure and microhardness of the welded joint was studied. The results show that the weld width at the side of the high oxygen TC4 in welded state is narrower than that of TC17. The symbiotic grains are form at the weld interface, dynamic recrystallization at both sides of the interface occurs. At the side of the high oxygen TC4, a large number of sub-grains form in the thermal affected zone （TMAZ） near the edge of the weld, and dynamic recrystallization occurs in part of TMAZ to form fine equiaxed β grains, finally martensite α＇ phase precipitates in grain after cooling. At the side of TC17, β grains and α grain boundaries are elongated to form deformation bands, and many fine equiaxed β grains are formed near the welding seam. After postweld heat treatment, the TMAZ metastable martensite α＇ phase of the high oxygen TC4 is decomposed, and the lamellar α phase is precipitated in the high deformed β phase. The TMAZ structure at the side of TC17 is fine acicular α phase, and the symbiotic grains in weld center is not uniform and consists of interlaced α lamellar. The hardness of the weld center in weld state is the highest. After heat treatment, the hardness of weld zone and TMAZ at the side of TC 17 increases greatly.

关 键 词：线性摩擦焊 微观组织 显微硬度 

分 类 号：TG453.9[金属学及工艺—焊接]