Ti-22Al-25Nb合金扩散连接工艺及连接机制研究  

Diffusion Bonding Process and Mechanism of Ti-22Al-25Nb Alloy

作　　者：付明杰 曾元松 钱健行 刘刚[2] Fu Mingjie;Zeng Yuansong;Qian Jianhang;Liu Gang(Aeronautical Key Laboratory for Plastic Forming Technology,Beijing Key Laboratory of Digital Plasticity Form-ing Technology and Equipment,AVIC Manufacturing Technology Institute,Beijing 100024,China;National Key Laboratory for Precision Hot Processing of Metals,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]中国航空制造技术研究院,塑性成形技术航空科技重点实验室,数字化塑性成形技术与装备北京市重点实验室,北京100024 [2]哈尔滨工业大学金属精密热加工国际级重点实验室,哈尔滨150001

出　　处：《稀有金属》2020年第12期1233-1239,共7页Chinese Journal of Rare Metals

基　　金：国家科技部支持(万人计划)项目(2069999)资助。

摘　　要：针对Ti-22Al-25Nb合金(Ti2AlNb合金)板材在温度为950~980℃、气压为2.0~3.5 MPa、时间为2~3 h下的真空扩散连接工艺及机制进行了研究。结果表明:影响Ti2AlNb合金扩散连接焊合率的最主要因素为表面粗糙度(Ra),当Ra小于0.2μm时,焊合率可在950℃,2.0 MPa下达到90%以上。揭示了Ti2AlNb合金扩散连接机制,通过采用单相区扩散连接对比试验和静态热处理试验,认为固溶温度下的扩散连接主要在压应力作用下,B2相和B2相的扩散连接是通过冷却析出的等轴O相颗粒实现焊缝连接;低于固溶温度扩散连接,O相与O相之间的连接通过大角度晶界转变为小角度晶界和晶界移动实现连接,而B2相与O相则通过应力诱发相变生成的B2相实现连接。The diffusion bonding processing and mechanism of Ti-22Al-25Nb alloy(Ti2AlNb alloy)under the conditions of tempera⁃ture of 950~980℃,pressure of 2.0~3.5 MPa and holding time of 2~3 h were studied.The results showed the most important factor ef⁃fecting quantity of diffusion bonding welding was roughness of material(Ra),welding rate could be better than 90%when the Ra was less than 0.2μm under 950℃and 2.0 MPa.The diffusion bonding and static heat treatment experiments were carried out atβphase zone,it was supposed that the mechanism of diffusion bonding of B2 phases was bonded through O phase precipitated at grain bound⁃ary of B2 phases under compressive stress.Diffusion bonding was applied below solution temperature,the main control mechanism of diffusion bonding between O phase and O phase was grain boundary transferred from high angle boundaries(HAB)to low angle bound⁃aries(LAB)and sliding parallel to the compressive direction to form a grain.The bonding of B2 phase and O phase was through stress induced transformation of O phase to B2 phase.

关 键 词：Ti2AlNb合金 扩散连接 显微组织 

分 类 号：TG132[一般工业技术—材料科学与工程]