SiBCN陶瓷和Ti₂AlNb合金瞬时液相扩散连接接头的微观组织和力学性能

A joint of SiCBN ceramic and Ti₂AlNB alloy was prepared via transient liquid phase diffusion bonding with AgCu fillers. The effects of joining temperature and holding time on the microstructure and mechanical properties of the joint were investigated. In joining, Ti dissolves from Ti₂AlNb alloy into Ag-Cu melt and reacts with SiBCN ceramic to form a continuous TiC interfacial layer, while Cu in the liquid phase diffuses towards Ti₂AlNb alloy to produce Nb(s, s) and TiCu₂Al, resulting in the isothermal solidification of melts. A thicken TiC layer appears, Cu(s, s) vanishes and the fraction of TiCu₂Al compound increases as the joining temperature or holding time increases. The shear strength at room temperature firstly increases and then decreases as the joining temperature or holding time increases. The joint prepared at 840 ℃ for 40^.min exhibits a maximum shear strength of (73±10) MPa and (95±16) MPa at room temperature and 500 ℃, respectively, which is mainly attributed to the good stress-relief ability and thermal resistance of Ag(s, s).