保温时间对瞬时液相扩散连接的Ti3Al /Ti2AlNb接头微观结构及力学性能的影响

Effects of Bonding Time on Microstructure and Mechanical Properties of Ti3Al/Ti2AlNb Joint Prepared by Transient Liquid Phase Diffusion Bonding

摘要:

采用Ni-Ti复合箔片作为中间层，在990 ℃、低连接压力（0.1 MPa）下，通过瞬时液相（TLP）扩散连接制备了Ti₃Al/Ti₂AlNb异种合金接头。分析了保温时间（10~90 min）对Ti₃Al/Ti₂AlNb接头微观结构及力学性能的影响，并研究了TLP扩散连接接头的界面演变和形成机制。结果表明，Ti₃Al/Ti₂AlNb接头具有典型的“Ti₃Al | Al_0.5Nb_0.5Ti₃ | 残余 Ni | NiTi | NiTi₂ | 残余 Ti | Al_0.5Nb_0.5Ti₃ | Ti₂AlNb”多层梯度结构。随着保温时间的延长，接头的抗剪切强度先增大后减小，当保温时间达到60 min时，Ti₃Al/Ti₂AlNb接头的抗剪切强度最大，达到167±12 MPa。另外，接头的断裂主要发生在Ti₂AlNb/Ti附近的NiTi₂层，并向Ti层延伸，呈现出脆性断裂的特征。

Abstract:

Using Ni-Ti duplex foils as joining materials, Ti₃Al alloy was bonded to Ti₂AlNb alloy by transient liquid phase (TLP) diffusion bonding at 990 °C under low bonding pressure (0.1 MPa). The effects of bonding time on the microstructure and mechanical properties of Ti₃Al/Ti₂AlNb joint were analyzed, as well as the interfacial evolution and forming mechanism of the TLP joint were studied. Results show that the Ti₃Al/Ti₂AlNb alloy joints with typical interface structure of Ti₃Al | Al_0.5Nb_0.5Ti₃ | residual Ni | NiTi | NiTi₂ | residual Ti | Al_0.5Nb_0.5Ti₃ | Ti₂AlNb can be formed. In addition, with the extension of bonding time, the shear strength of the joint first increases and then decreases, and the maximum shear strength, up to 167±12 MPa, of the Ti₃Al/Ti₂AlNb alloy joint can be achieved when the bonding time reaches 60 min. The joint fracture, characterized by brittle fracture, mainly occurs at the NiTi₂ layer adjacent to the Ti₂AlNb/Ti interlayer and extends to the Ti interlayer.