Effects of microfluidic morphologies on the interfacial microstructure and mechanical properties of Ti₃SiC₂ ceramic and pure copper brazed joints

Brazing is a crucial technology in the field of precision joining. In this work, microfluidic systems with different morphologies were fabricated on the surface of a Ti₃SiC₂ ceramic by vapour deposition and fine laser etching. The effects of microfluidics on the microstructure and mechanical properties of the Ti₃SiC₂ ceramic and the Cu brazed joints were investigated with SEM, TEM and shear strength tests. The width of the Ag–Cu eutectic zone in the brazing seam varied with the microfluidic morphology, which was attributed to the differences in liquid filler wettability in the different microfluidic systems. The interfacial structure of the joint coated with a Ni metal layer was Cu/Ag–Cu eutectic/Ti₅Si₃+CuTi + TiC + Ti₂Ni + Ni₃Ti/Ti₃SiC₂ ceramic. In addition, the highest joint strength realized with microfluidics reached 116.9 MPa, which was 15.4% higher than those of joints brazed with smooth ceramics. This work provides theoretical and technical guidance for the field of precision brazing.