Microstructure and Mechanical Properties of SiC Joint Brazed by Al-Ti Alloys as Filler Metal

SiC ceramic has excellent overall properties, and joining it to other materials with high joint strength is an important issue in the actual applications.Brazing of SiC ceramic to itself was performed using the as-fabricated Al-(10, 20, 30, 40)Ti alloys with nominal Ti concentrations of 10%, 20%, 30%, and 40% at 1550 ℃ × 30 min.The average joint shear strength fluctuates in the range of ~100-260 MPa with the interlayer thickness of ~50 μm.Moreover, the average strength SiC/Al-20Ti/SiC joint is increased markedly with the interlayer thickness decreasing from ~100 to 25 μm, reaching the maximum of ~315 MPa.Meanwhile, the (Al) phase in the interlayers is reduced gradually till disappear with the thinnest brazing interlayer, leaving the Al 4 C 3 , TiC and (Al,Si) 3 Ti phases in the interlayer.The joint fractures of SiC/Al-20Ti/SiC joint mainly occur in the SiC ceramic substrate near the interlayer/ceramic interface.