液-固扩散焊复合连接Ti(C,N)与40Cr的界面行为与接头强度

通过预置Ti/Cu非对称中间层对Ti(C,N)基金属陶瓷与40Cr钢进行了液-固扩散焊复合连接试验,重点研究了界面组织、接头强度及其影响因素.结果表明,通过预置Ti/Cu非对称中间层液-固扩散焊,能够分别实现Ti(C,N)基金属陶瓷与铜箔,以及铜箔与40Cr钢之间的冶金结合;Ti(C,N)基金属陶瓷界面物相呈梯度分布,形成Ti(C,N)基金属陶瓷/TiAl₂/Ti₂Cu/TiCu/铜箔结构;Ti(C,N)基金属陶瓷一侧靠近界面区域存在较大的焊接残余拉应力,以及脆弱的TiAl₂金属间化合物层,是制约焊接接头强度的关键因素;单纯以铜箔为中间层,采用常规固相扩散焊连接Ti(C,N)基金属陶瓷,即使在加热温度1223 K、压力20 MPa条件下,也难以实现Ti(C,N)基金属陶瓷与铜箔的有效连接.

Interfacial behavior and joint strength of Ti (C,N) and 40Cr joints obtained by liquid-solid diffusion hybrid bonding method

By preseting asymmetric Ti/Cu interlayer,liquid-solid diffusion bonding of Ti(C,N)-based cermet and 40Cr was performed. The interfacial microstructure,joint strength and their effect factor were investigated. The results showed that, through preseting asymmetric Ti/Cu interlayer,the metallurgic bondings between Ti (C,N)-based cermet and Cu foil and between Cu foil and 40Cr steel can be achieved in liquid-solid diffusion welding, respectively. The phase at the interface of Ti(C,N)-based cermet has gradient distribution, forming Ti(C,N)-based cermet/TiAl₂/Ti₂Cu/TiCu/Cu foil structure. There exists large welding residual tensile stress and brittle TiAl₂ intermetallic compounds in the interface zone close to Ti(C,N) based cermet,being the key factor of restricting the strength of welded joint. By only using Cu foil as interlayer,it is difficult to join Ti(C,N) based cermet to Cu foil effectively in solid diffusion welding of Ti(C,N) based cermet even at the heating temperature of 1 223 K and the pressure of 20 MPa.