Design of low temperature brazing filler metal for graphite/Al together with microstructure and properties of brazed joints

Objective The aim is to achieve a good connection of joints between graphite and Al. Methods A new low-temperature brazing filler metal AgCu28In35Ti2 is designed. By adding In element, it undergoes eutectic reaction with Ag and Cu to lower melting point, thereby achieving good connection of joints between graphite and Al. Results The research results show that during the brazing process, compounds with relatively uniform distribution of Al₂Cu, AgIn₂, and TiAl₃ are formed in brazed joints. At the same time, a large amount of In precipitates along grain boundaries of base material. Under the parameters of brazing temperature of 620 ℃ and holding time of 30 min, strength of brazed joints reaches a maximum of 14.85 MPa. Conclusion The designed low-temperature brazing filler metal AgCu28In35Ti2 provides a good method for high reliability connection of graphite/Al.