Ti_3Al和Ti_2AlNb合金扩散连接界面的组织及力学性能  

Interfacial Microstructure and Mechanical Properties of Diffusion Bonding of Ti_3Al and Ti_2AlNb Alloys

作　　者：李万青[1,2] 魏红梅[1] 何鹏[1] 高丽娇[1,3] 林铁松[1] 李小强[1] 赫兰春 

机构地区：[1]哈尔滨工业大学先进焊接与连接国家重点实验室,哈尔滨150001 [2]北京航空材料研究院,北京100095 [3]北京星航机电装备有限公司,北京100074

出　　处：《材料工程》2015年第1期37-43,共7页Journal of Materials Engineering

基　　金：国家自然科学基金资助项目(51275135;51305102);高等学校博士学科点专项科研基金优先发展领域课题(20112302130005)

摘　　要：采用直接扩散连接Ti3Al和Ti2AlNb合金,研究了连接压力、连接温度、保温时间等工艺参数对接头界面组织形貌及性能的影响。利用扫描电镜、能谱分析和X射线衍射等方法观察分析了界面组织结构,并测试了接头的力学性能。结果表明:直接固相扩散连接接头的典型组织为Ti3Al/O相+α2相过渡层/富B2层/Ti2AlNb。当连接温度为1000℃,保温时间60min,连接压力为5MPa时获得的接头室温抗剪强度为635MPa,室温抗拉强度为795MPa,均断裂于Ti3Al母材一侧。经1000℃/60min热循环后Ti3Al母材的抗拉强度下降至原始母材的76%。连接温度低于950℃或保温时间小于60min会导致未焊合等缺陷;温度高于1050℃或保温时间超过120min则导致Ti3Al发生相变。Ti3A1 and Ti2A1Nb alloys were joined by direct diffusion welding. The influence of bonding pressure, bonding temperature and holding time on the interface morphology and property of the joint was studied. The interface structure was analyzed by SEM, EDS and XRD, and the mechanical prop- erties of joints were tested. The results show that typical interface structure of direct diffusion bond- ing joints is Ti3A1/O-phase and α2-phase/B2-rich phase/Ti2A1Nb. When bonding temperature is 1000~C, holding time is 60min, bonding pressure is 5MPa, the shear strength could reach 635MPa and the tensile strength could reach 795MPa. Both joints fracture at the TiaAl-base alloy. After thermal cycling （1000℃/60min）, the tensile strength of Ti3Al decreases to 76% of the original strength, Welding defects occur when bonding temperature is below 950℃ or holding time is less than 60min. The bonding temperature higher than 1050℃ or holding time more than 120min will lead to phase transition of Ti3A1.

关 键 词：扩散连接 TI3AL合金 Ti2AlNb合金 微观组织 性能 

分 类 号：TG453.9[金属学及工艺—焊接]