钨和钨合金真空固态压力扩散连接

Joining of Tungsten with Tungsten Alloy Using Vacuum Solid-state Pressure Diffusion Bonding

以高纯铁粉为中间层,采用真空扩散连接实现纯W与W-60Fe合金材料的高强度连接,研究了连接工艺对元素扩散、连接性能和中间层组织、断口组织的影响。结果表明:连接界面发生梯度扩散并产生冶金结合,随扩散温度升高,W、Fe扩散距离呈抛物线性正增长;随扩散时间延长、施加压力增大,扩散距离都显著增大;且在W/Fe界面和(W-60Fe)/Fe界面,W在Fe中的扩散距离要大于Fe在W中的扩散距离。在温度850℃、压力50 MPa、保温时间2 h条件下,中间层组织最为致密,界面连接强度最高为182 MPa。在此工艺水平下,继续升高连接温度、延长保温时间和增大保压压力,都会使连接界面晶粒粗化,从而使界面连接强度出现降低。连接界面强度超过母材钨的强度,连接样品拉伸断裂主要发生在W的部分。

Vacuum solid-state pressure diffusion bonding was adopted to realize the high strength metallurgical bonding of pure W with W-Fe material, the influences of bonding technology on interlayer microstructure, element diffusion,bonding properties as well as fractograph were investigated, the results show that: Gradient diffusion subsequent with metallurgical bonding occur at joining interface;With the increasing of temperature, diffusion distance of W, Fe atoms grow comply with a positive parabolic linear relationship;With the extension of diffusion time or pressure increase,significant increase occurs in diffusion distance;At W/Fe interface and(W-Fe)/Fe interface, the diffusion distance of W in Fe is longer than that of Fe in W. Under the condition of 850 ℃, 50 MPa pressure, 2 h heat preservation time, interlayer microstructure is most dense, and bonding strength reaches highest value, which is 182 MPa. Based on this technological level, decreasing/increasing diffusion temperature and prolonging holding time and increase the holding pressure will lead to grain coarsening in bonding interface, and then lead to decrease in bonding strength. Bonding strength exceeds the strength of the tungsten parent, so tensile fracture occurs mainly in W part.