Improvement for interfacial microstructure and mechanical properties of ti₃sic₂/cu joint brazed by ag-cu-ti filler with copper mesh

Ti₃SiC₂ ceramic and copper were successfully vacuum brazed using Ag-Cu-Ti filler and Ag-Cu-Ti filler with copper mesh, respectively. In this study, the effects of copper mesh and brazing parameters on the interface microstructure and mechanical properties of the joints were systematically studied. The results revealed that the typical interfacial microstructure of joint was Ti₃SiC₂ ceramic/Ti₅Si₃ + TiC + Ti₂Cu + Ti₃Cu/Ag (s, s) + Cu (s, s)/eutectic Ag-Cu + TiSiCu/Cu. A maximum shear strength of joint obtained at a brazing temperature of 870^◦C and a holding time of 10 min can reached up to 66.3 ± 1.2 MPa, which was 34.7% higher than that without copper mesh. The improvement of mechanical property was attributed to the extraordinary plasticity of copper mesh, which reduced the residual stress caused by the difference in the coefficient of thermal expansion at the interface of joints. As the brazing temperature and holding time further increased, the shear strength of joints decreased due to the excessively thick reaction layer of intermetallic compounds.