Study on the vacuum brazing of diamond/Cu composite material and diamond film with Ag-Cu-Ti active filler metal

Ag-Cu-Ti active filler metal was used as the solder material to effectively achieve the high-strength connection between the diamond/Cu composites and diamond film. The microstructure, brazing quality and mechanical properties of the joint were characterized by SEM, ultrasonic non-destructive test and tensile test respectively. The reliability of the brazed joint was verified by thermal cycle experiments. The results show that by adding the active element Ti, a uniform continuous layer Ti-riched phase is determined at the joint between the solder and diamond film, which greatly improves the wettability of the solder and diamond film. The joint with high-quality, low defects and high thermal conductivity is obtained from the smooth diamond film rather than the rough diamond film. The maximum tensile strength of the joint is greater than 23.12MPa and the joint can sustain 50 thermal cyclings, which can meet the requirements of practical application.