添加稀土元素的TC4钛合金激光焊接头纵向超塑性能研究  

Study on the longitudinal superplastic properties of TC4 titanium alloy laser welded joint with rare earth elements

作　　者：程东海[1] 张声金 陶玄宇 张华 张夫庭 亓安泰 肖雄 CHENG Donghai;ZHANG Shengjin;TAO Xuanyu;ZHANG Hua;ZHANG Futing;QI Antai;XIAO Xiong(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang,330000,China;School of Mechanical Engineering,Beijing Institute of Petrochemical Technology,Beijing,102617,China)

机构地区：[1]南昌航空大学,航空制造工程学院,南昌330063 [2]北京石油化工学院,机械工程学院,北京102617

出　　处：《焊接学报》2024年第7期19-26,共8页Transactions of The China Welding Institution

基　　金：国家自然科学基金项目(51965045);江西省自然科学基金项目(20212BAB204044)。

摘　　要：针对钛合金激光焊接接头超塑性能低的难题,提出在焊缝中以Yb_(2)O_(3)的方式添加稀土Yb元素,分析Yb_(2)O_(3)含量对TC4钛合金激光焊接头高温拉伸峰值流变应力、断后伸长率及组织的影响.结果表明,Yb_(2)O_(3)能够促进变形过程的组织等轴化进程,减小焊缝β晶粒尺寸和接头超塑性变形流变应力,并提高断后伸长率.随着Yb_(2)O_(3)含量增加,接头应力应变曲线下移,峰值流变应力呈先降低后升高的趋势,而断后伸长率则为先增大后减小.在超塑性变形过程中,Yb_(2)O_(3)含量6%时峰值流变应力最低为11.9 MPa,断后伸长率为572.3%;焊缝中心β晶粒尺寸最小为127μm,相较于未添加Yb_(2)O_(3)时β晶粒尺寸的337μm细化了62.3%.此时,马氏体组织发生相变,形态转变成片层,焊缝区域组织等轴化程度最高,焊缝的超塑性能最好.Aiming at the problem of low superplasticity of titanium alloy laser welded joints,this paper proposes to add rare earth Yb element in the form of Yb_(2)O_(3)in the weld,and analyzes the effects of Yb_(2)O_(3)content on the peak flow stress,elongation and microstructure of laser welded joint of TC4 titanium alloy at high temperature.The results show that Yb_(2)O_(3)can reduce theβgrain size of the weld and the superplastic deformation flow stress of the joint,increase the elongation,to promote the equiaxed process of the deformation process.With the increase of Yb_(2)O_(3)content,the stress-strain curve of the joint moves down,the peak flow stress decreases first and then increases,while the elongation increases first and then decreases.In the process of superplastic deformation the lowest peak flow stress is 11.9 MPa and the elongation is 572.3%when the content of Yb_(2)O_(3)is 6%.The minimum grain size ofβin the weld center is 127μm,which is 62.3%finer than the 337μm of theβgrain size without Yb_(2)O_(3).At this time,the martensitic structure undergoes phase transformation,the morphology changes into lamellar,the degree of equiaxed structure in the weld area is the highest,and the superplasticity of the weld is the best.

关 键 词：Yb_(2)O_(3)含量 激光焊 TC4钛合金 超塑性能 

分 类 号：TG457.1[金属学及工艺—焊接]