TC4钛合金激光自熔焊焊接组织及性能  

Microstructure and mechanical properties of TC4 titanium alloy by autogenous laser welding

作　　者：张世伟 王珏 佀好学 刘颖 张博贤 Zhang Shiwei;Wang Jue;Si Haoxue;Liu Ying;Zhang Boxian(Aeronautical Key Laboratory for Welding and Joining Technologies,AVIC Manufacturing Technology Institute,Beijing 100024,China;The Sixth Military Representative Office of Airforce in Beijing,Beijing 100024,China)

机构地区：[1]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 [2]空军装备部驻北京地区第六军事代表室,北京100024

出　　处：《焊接》2024年第6期33-39,46,共8页Welding & Joining

摘　　要：【目的】该文旨在研究焊接接头各个区域的组织特征、显微硬度及力学性能,以实现钛合金高效高质量焊接。【方法】以3 mm厚TC4钛合金为试验材料,采用YAG激光焊接方法进行了对接试验。【结果】结果表明,激光焊接TC4钛合金能够获得了成形良好的焊接接头,无裂纹及气孔等缺陷。焊缝组织为典型的网篮组织,由大量的αʹ马氏体相和少量的高温残留β相构成,热影响区为交错排布的针状αʹ马氏体。焊接接头的显微硬度呈驼峰分布,从母材到热影响区逐渐增加,焊缝内部区域的平均硬度约为385 HV,均大于母材(约为360 HV),这是由于在热循环作用下,焊缝凝固时发生了马氏体转变,β相向针状αʹ相转变所致。焊接接头断裂位置位于母材区域,断口形貌均呈现大小不一的等轴性韧窝形貌,为韧性断裂模式。弯曲测试和冲击测试表明,焊接接头具有良好的塑性和韧性。【结论】综上可知,激光焊接TC4钛合金能够获得良好的焊缝成形,可在相关工程中推广应用。[Objective]The purpose of the paper was to study microstructure,microhardness,and mechanical properties of welded joints in order to realize high efficiency and high-quality welding of titanium alloy.[Methods]Taking 3 mm thick TC4 titanium alloy as test material,butt welding experiment of was carried out by YAG laser welding method.[Results]The results showed that laser welding of TC4 titanium alloy could obtain well-formed welded joints without defects of cracks and pores.Microstructure of weld was typical net basket microstructure,consisting of a large number ofαʹmartensite phase and a small amount of high-temperature residueβphase,heat affected zone was acicularαʹmartensite with staggered arrangement.Microhardness of welded joints showed a hump distribution,and gradually increased from base metal to heat affected zone.Microhardness of internal zone of weld was about 385 HV,which was greater than that of base metal(about 360 HV).This was due to martensite transformation of weld during solidification under the action of thermal cycling,which was caused by transformation ofβto acicularαʹphase.Fracture position of welded joints was in the base metal.Fracture morphology showed morphology of equiaxial dimple with different sizes,which was a ductile fracture mode.Bend and impact tests indicated that welded joints had good plasticity and toughness.[Conclusion]In summary,laser welding of TC4 titanium alloy could achieve good formation of weld,which could be promoted and applied in related engineering.

关 键 词：激光焊接 TC4钛合金 微观组织 显微硬度 力学性能 

分 类 号：TG442[金属学及工艺—焊接]