The impact of TiC particle addition to Ag-Cu-Ti filler material on the microstructure and mechanical properties of AlN ceramic/Cu brazed joints

The thermal expansion coefficient difference between AlN ceramics and Cu leads to thermal stress during brazing, which reduces the strength of the joint. Adding low thermal expansion coefficient particles to the brazing filler metal can alleviate the residual stress of the joint. In this study, AlN ceramics and Cu were successfully brazed using TiC/Ag-Cu-Ti composite filler metal at 900 degree celsius. By changing the content of TiC, the effects on the microstructure and mechanical properties of the joints were investigated. The results show that the interfacial structure of the joints is AlN/TiN/Ag solid solution + Cu solid solution + CuTi + TiC/Cu. The addition of TiC particles effectively alleviates the thermal mismatch of the joints and can refine the structure and improve the mechanical properties of the joints. The joint strength increases and then decreases with the increase of TiC content. When the TiC content is 12 wt.%, the shear strength of the joint is the largest, reaching 120.9 MPa. The peak strength is approximately 81% higher than the case without TiC addition.