电场激活Ti/Ni扩散偶连接界面相变规律与力学性能的研究

本试验采用电场激活扩散连接技术(FADB)实现了Ti/Ni的扩散连接。研究了Ti/Ni两种材料发生界面扩散反应时新相的生成规律及其对连接强度的影响。利用扫描电子显微镜及能谱仪观察和分析了扩散层的显微组织、相组成和界面元素分布。采用万能试验机对扩散层的抗剪切性能进行了测试。研究结果表明,在电场作用下,Ti与Ni通过固相扩散形成了良好的冶金结合界面,界面处金属间化合物的生成次序依次为Ni3Ti、Ni Ti2、Ni Ti。当扩散温度≥750℃时,Ti表现出超塑性和良好的扩散性,促使扩散层中的Ni3Ti转变成富钛层,该富钛层的形成有利于接头强度的提高。界面的剪切强度随着电流的增大而增大,当电流为930~1200 A时,界面的剪切强度可达90.54 MPa。

Phase Transformation and Mechanical Performance of Interface between Ti/Ni

The diffusion bonding between Ti/Ni was carried out by Field Activated Diffusion Bonding process (FADB). The formation of new phase during interfacial diffusion reaction between Ti/Ni and its effect on bonding strength were studied. The microstructure, phase component and element distribution across interfaces were observed and determined by SEM and EDS. The shearing properties of bonded interface were evaluated by a universal testing machine. The results indicate that complete metallurgical bonding between Ti/Ni has been reached, which is composed of intermetallics of Ni3Ti, NiTi2 and NiTi in order. When the diffusion bonding temperature is as high as 750 oC, Ti shows good performance of superplasticity and high diffusivity, which promotes Ni3Ti to transform into Ti-rich layer during diffusion bonding. The formation of Ti-rich layer improves the shearing strength of interface. The shearing strength of the Ti/Ni interface increases with increase of current, and when the current is 930~1200 A, it reaches 90.54 MPa