Abstract: Aiming at the poor workability of the novel high-temperature-resistant composites(SiC_f/SiC), the brazing of SiC_f/SiC and a Ni-base superalloy is studied. The mechanical properties and microstructural evolution of joints at different temperatures are studied, and the corresponding mechanism is clarified. Under the process parameters of 1 050℃/10 min, the room temperature shear strength of the joint reaches 79 MPa. The typical interface structure of the joint was GH536/(Ni, Cr, Mo, Fe)+TiNi₃+Ti₂Ni+AuCu_I/TiNi₃+Ti₂Ni+TiNi+AuCu_I/σ/Mo/Mo_4.8Si₃C_0.6/Ti₅Si₃C_x/Ti₅Si₃C_x+TiC+AuCu_I/Ti₃SiC₂/SiC_f/SiC. When the temperature is low, the interface reactions are limited. Therefore, it is difficult to form a continuous connection Ti₅Si₃C_x+TiC layer at the ceramic/braze heterogeneous interface. When the brazing temperature increases to 1 050℃, a 3 μm layer of Ti₃SiC₂ newly forms at the heterogeneous interface to achieve efficient connection. When the temperature continues to rise to 1 100℃, the diffusion of Cr element in Mo foil increases, and an enrichment of Cr occurs at the heterogeneous interface of ceramic/braze. Currently, the excessively thick interfacial reaction layer(10 μm)is the main reason for the reduction of joint shear strength. The use of this brazing system helps to hinder the violent reactions between the base materials and relieve the thermal stress of the joint, which reduces the processing difficulty of SiC_f/SiC in practical applications.

Key words: SiC_f/SiC composites, GH536, Mo interlayer, microstructure, mechanical properties