Ti-61Ni真空钎焊TZM合金接头界面组织与力学性能

Interfacial Microstructure and Mechanical Properties of TZM Alloy Joints Brazed Using Ti-61Ni Filler Metal

目的研究不同钎焊温度下获得TZM/Ti-61Ni/TZM接头的微观组织演化及力学性能的变化,为获得可靠钎焊接头提供指导。方法采用电弧熔炼方法制备Ti-61Ni,将以TZM/Ti-61Ni/TZM“三明治”结构装配的试样放入真空炉中进行不同温度(1200~1280℃)下的钎焊连接,利用SEM和EDS等手段分析钎料与母材之间的相互作用,测试接头的力学性能并分析接头断裂行为,研究温度对接头界面组织演化和力学性能的影响。结果钎缝主要为TiNi相和TiNi3相,钎料中Ti元素向母材扩散形成Mo(s,s)扩散层;钎焊温度升高,钎缝宽度减小,TiNi相减少,钎料对TZM母材的溶蚀加剧;接头的抗剪强度先升高后下降,接头在TZM母材处断裂。结论采用Ti-61Ni高温钎料实现了TZM合金的可靠连接,接头典型界面组织为TZM/扩散层(Mo(s,s))/TiNi+TiNi3/扩散层(Mo(s,s))/TZM;当钎焊温度为1240℃时,接头的抗剪强度达到最大值,为121 MPa。

To obtain reliable brazed joints,the evolution of interfacial microstructure and mechanical properties of TZM/Ti-61Ni/TZM joints brazed at different temperature were investigated.The Ti-61Ni filler alloy was prepared by arc melting method.The samples were assembled as sandwich structure of TZM/Ti-61Ni/TZM and then brazed in a vacuum furnace at different temperatures(1200~1280℃).The interactions between the filler alloy and the base metal were analyzed by SEM and EDS.The mechanical properties of joints were tested and the fracture behavior of the joints was analyzed.The effects of brazing temperature on the evolution of interfacial structure and mechanical properties of the joint were studied.The brazed seam mainly con-sists of TiNi phase and TiNi3 phase.The element Ti in the filler alloy diffuses to the base metal,forming the diffusion layer(Mo(s,s)).With the increase of brazing temperature,the width of brazed seam and the content of TiNi phase decrease,and the dissolution of TZM alloy into liquid filler alloy is enhanced.Also,the shear strength of joints increases firstly and then de-creases,and the joints break at TZM base metal.Ti-61Ni filler alloy is used to realize the reliable joining of TZM alloy.The typical interfacial microstructure of the joint is TZM/diffusion layer(Mo(s,s))/TiNi+TiNi3/diffusion layer(Mo(s,s))/TZM.The maximum shear strength of 121 MPa is achieved when the brazing temperature is 1240℃.