Study on Joining SiC with Ti₃SiC₂ Phase In-situ Formed by Vacuum Pressureless Brazing and Its Mechanical Properties

The vacuum brazing of SiC was carried out with TiSi₂ powder and Si powder mixed filler metal, and the connection of SiC ceramics was realized.The microstructure evolution of SiC joints under different joining temperatures and holding time was revealed by microstructure characterization, and the normal temperature mechanical properties of SiC joints under different brazing processes were tested.The results show that under 1400 ℃ for 3 h or 1500 ℃ for 2 h, the filler metal can react with SiC in situ to form dense and continuous Ti₃SiC₂ (MAX) phase, the increase of joining temperature can shorten the holding time needed for MAX synthesis.The average room temperature shear strength of SiC joints held at 1400 ℃ for 3 h and 1500℃ for 2 h is 98, 151 MPa, respectively.The weld joint obtained at 1500 ℃ forms a serrated interface with the SiC ceramic matrix, which enhances the mechanical connection strength between the weld and the base metal.