光束摆动和氮气合金化对钼合金接头组织和性能的影响  

Effect of beam oscillating and nitrogen alloying upon microstructure and mechanical properties in laser welding of molybdenum alloy

作　　者：于涵 潘隆政 张林杰[1] 梁文生 白立安 YU Han;PAN Longzheng;ZHANG Linjie;LIANG Wensheng;BAI Li′an(State Key Laboratory of Mechanical Behavior for Materials,Xi′an Jiaotong University,Xi′an,710049,China;Xi′an Yuanfei Aviation Technology Development Co.,Ltd.,Xi′an,710089,China)

机构地区：[1]西安交通大学,金属材料强度国家重点实验室,西安710049 [2]西安远飞航空技术发展有限公司,西安710089

出　　处：《焊接学报》2022年第5期49-55,I0006,I0007,共9页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(51775416)。

摘　　要：钼合金熔化焊接存在晶粒粗大、晶间偏析问题,导致接头力学性能差,采用激光束摆动和氮气合金化方法开展试验研究.结果表明,单独采用光束摆动措施后,焊缝区平均晶粒尺寸减小约28%,焊缝中心显微硬度从190 HV提高到200 HV,钼合金对接接头抗拉强度从29.83 MPa提高到130.03 MPa.单独采用氮气合金化(保护气体10%N_(2)+90%Ar)的方法后,焊缝中心显微硬度从190 HV提高到240 HV,钼合金对接接头抗拉强度从29.83 MPa提高到350.94 MPa;在同时采用激光摆动与氮气合金化时接头抗拉强度达到了439.43 MPa,为母材抗拉强度的67.8%,且断裂模式由沿晶断裂转变为了沿晶断裂与穿晶解理断裂并存;分析认为氮气合金化对接头性能的强化效果得益于晶内和晶界处Mo_(2)N相的生成.The problems of coarse grains and intergranular segregation in molybdenum alloy welding lead to poor mechanical properties of the joints.The experimental study was carried out by using laser beam oscillation and nitrogen alloying.The results show that when using beam oscillating only,the average grain size in the weld zone was reduced by about 28%,the microhardness of the weld center was increased from 190 HV to 200 HV,and the tensile strength of molybdenum alloy joint was increased from 29.83 MPa to 130.03 MPa.When using nitrogen alloying only(shielding gas 10%N_(2)+90%Ar),the microhardness of weld center was increased from 190 HV to 240 HV,and the tensile strength of molybdenum alloy joint was increased from 29.83 MPa to 350.94 MPa.Furthermore,the tensile strength of the joint reached 439.43 MPa which was 67.8%of the tensile strength of the base metal when laser oscillating and nitrogen alloying were used simultaneously,and the fracture mode changes from intergranular fracture to intergranular fracture and transgranular cleavage fracture.The analysis shows that the strengthening effect of nitrogen alloying on the properties of the joint benefits from the formation of Mo_(2)N phase in the grain and at the grain boundary.

关 键 词：钼合金 光束摆动 晶粒细化 氮气合金化 

分 类 号：TG456.7[金属学及工艺—焊接]