Interface Structures and Bonding Strength of SiC/TiAl Joints in Diffusion Bonding

Diffusion bonding of Pressureless-sintered SiC ceramic to TiAl intermetallic compound was carried out. The kinds of the reaction products and the interface structures of the joints were investigated by SEM, EPMA and XRD. The bonding strength of the joints was evaluated by tension-shear test. The experimental results showed that the three kinds of new phases,TiAl₂, TiC and Ti₅Si₃C_X, occur during the diffusion bonding of SiC to TiAl and that the interface structures of the joints can be expressed by SiC/TiC/(TiC+Ti₅Si₃C_X)/(TiAl₂+TiAl)/TiAl. The shear strength of the joint, which was bonded at 1573 K for 1.8 ks, is up to 240 MPa at room temperature and 230 MPa at the test temperature of 973 K.