TB18钛合金电子束焊接接头微观组织及力学性能研究  

Research of Microstructure and Mechanical Properties of Electron Beam Welding Joints for TB18 Titanium Alloy

作　　者：耿康 徐明 刘昕 付鹏飞 李立航 唐振云 GENG Kang;XU Ming;LIU Xin;FU Pengfei;LI Lihang;TANG Zhenyun(Science and Technology on Power Beam Processes Laboratory,AVIC Manufacturing Technology Institute,Beijing 100024,China)

机构地区：[1]中国航空制造技术研究院高能束流加工技术重点实验室,北京100024

出　　处：《航空制造技术》2024年第21期76-84,共9页Aeronautical Manufacturing Technology

基　　金：国防基础科研计划(JCKY2022205A001)。

摘　　要：TB18钛合金是一种新型近β型超高强韧钛合金,其高比强度、高比刚度的特征受到航空航天领域的青睐。本研究对TB18钛合金采用3种电子束焊接和热处理组合工艺获得焊接接头,并通过组织分析、拉伸和冲击性能测试、断口分析研究了焊接接头的微观组织和力学性能的关系。结果表明,TB18钛合金电子束焊接接头由母材、热影响区和熔化区3个区域组成。在3种电子束焊接和热处理组合工艺中,固溶+时效+焊接态的熔化区为较软的β相,力学性能强度低但塑性高。而固溶+焊接+时效态、焊接+固溶+时效态3个区域的微观组织均为β相析出细小弥散的针状α相。但前者的熔化区针状α相长径比低,力学性能强度高,塑性差,呈现脆性断裂。焊接+固溶+时效态3个区域的α相长径比相对均一,力学性能强度高,塑性良好,呈现强韧性匹配特征,因此是最优的电子束焊接和热处理组合工艺。TB18 titanium alloy is a new type of near-βultra-high strength titanium alloy,whose high specific strength and high specific stiffness are favored by the aerospace field.Three electron beam welding and heat treatment processes were used to obtain welded joints of TB18 titanium alloy,the relationship between the microstructure and mechanical properties of welded joints are researched through microstructure analysis,tensile and impact property testing,fracture analysis.Results show that TB18 titanium alloy electron beam welded joints consist of the base material,heat-affected zone and fusion zone.In three electron beam welding and heat treatment processes,the fusion zone of solid solution+aging+welding state is composed of the softerβphase,resulting in its mechanical properties show lower strength and higher plasticity.The microstructure of the three regions of solid solution+welding+aging state,welding+solid solution+aging state areβ-phase precipitated fine dispersed acicularα-phase.But the former in the fusion zone the ratio of length to diameter of acicularαphase is low,resulting in high strength,poor plasticity and brittle fracture.The ratio of length to diameter of welding+solid solution+aging state in three regions is uniform,so its high strength and good plasticity indicate strength and toughness matching characteristics,hence,it is the optimal electron beam welding and heat treatment process scheme.

关 键 词：TB18钛合金 电子束焊接 热处理 组织 力学性能 断口分析 

分 类 号：TG456.3[金属学及工艺—焊接]