Laser welding of molybdenum socket joint for ultra-high-temperature heat pipes based on niobium alloying  

超高温钼热管套接接头的铌合金化激光焊接

作　　者：Jia-xuan ZHAO Hong-da ZHANG Lin-jie ZHANG Xiang-dong DING Yuan-jun SUN Guang SUN 赵佳璇;张洪达;张林杰;丁向东;孙院军;孙广(西安交通大学金属材料强度国家重点实验室,西安710049;中国广核集团有限公司,深圳518172)

机构地区：[1]State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China [2]China Nuclear Power Design Co.,Ltd.,Shenzhen 518172,China

出　　处：《Transactions of Nonferrous Metals Society of China》2025年第2期511-524,共14页中国有色金属学报(英文版)

基　　金：National Key Research and Development Project of China (No. 2022YFB3707602);National Natural Science Foundation of China (Nos. 52005393, 51775416)。

摘　　要：The influence of Ti and Zr,Nb alloying on the microstructures and performance of laser-welded molybdenum socket joints was investigated.Following Nb alloying,the average microhardness of the fusion zone(FZ)increased from HV 194.7 to HV 283.3.Additionally,Nb can react with O to form dispersed Nb_(2)O_(5) along grain boundaries,impeding grain boundary migration and dislocation movement while reducing the content of volatile Mo oxide along these boundaries.The incorporation of Nb in FZ partially inhibits pore defects and enhances joint load-bearing capacity.In comparison to the laser-welded joints without adding Nb(LW),the tensile strength of the laser-welded joints with Nb alloying(LW-Nb)was significantly improved by approximately 69%from 327.5 to 551.7 MPa.Furthermore,the fracture mechanism of the joints transitioned from intergranular fracture to transgranular fracture.研究Nb合金化对激光焊接钼套接接头显微组织和性能的影响。Nb合金化后,焊缝区(FZ)的平均显微硬度由HV 194.7提高到HV 283.3。Nb与O结合形成Nb_(2)O_(5),Nb_(2)O_(5)分散在晶界上,从而阻碍了晶界迁移和位错运动,并降低了晶界处挥发性Mo氧化物的含量。在FZ中加入Nb在一定程度上抑制了孔隙缺陷的危害,提高了接头的承载能力。与未添加Nb的接头(LW)相比,添加Nb合金的激光焊接接头(LW-Nb)的抗拉强度从327.5 MPa提高到551.7 MPa,提高了约69%。此外,接头断裂机理由沿晶断裂转变为穿晶断裂。

关 键 词：laser welding MOLYBDENUM heat pipe niobium alloying MICROSTRUCTURE performance 

分 类 号：TG456.7[金属学及工艺—焊接]