Microstructure and property of SiC ceramic brazed joint filled with Ti foam/AlSiMg filler metal

In order to enrich the design ideas of brazing filler metal for SiC ceramic, a novel Ti foam/AlSiMg composite filler has been proposed. The interfacial adhesion between the filler metal and SiC ceramic was improved by the dissolution of Ti element, and the in-situ reinforced brazing seam was obtained by the reaction between Ti foam and AlSiMg metal which improved the mechanical property of the joint. Vacuum brazing of SiC ceramics was carried out with brazing temperature of 700 ℃, holding time of 60 min and welding pressure of 10 MPa. Microstructure, composition and properties of the joints were analyzed by optical microscope, scanning electron microscope, energy dispersive spectrometer, X-ray diffractometer, electron microprobe analysis, and shearing test. The applicability of Ti foam/AlSiMg filler metal for SiC ceramic brazing was explored. The results show that the structure of the joint with Ti foam/AlSiMg filler was "SiC/Al/Ti(Al,Si)₃/ Ti(Al,Si)₃ in-situ reinforced Ti based brazing seam/Ti(Al,Si)₃/Al/SiC". The fracture occurred between the Al alloy interfacial layer and SiC ceramic. The dissolution of Ti in the liquid Al alloy improved the interfacial adhesion between Al alloy interlayer and SiC ceramic. The shearing strength of the joint with Ti foam/AlSiMg filler metal was 111 MPa.