Effect of brazing temperature on microstructure and mechanical properties of TiAl/ZrB2 joint brazed with CuTiZrNi filler

The TiAl alloy and ZrB2-SiC ceramic are promising materials used at high temperature. One route to extend their unique applications under extreme conditions relies on successful brazing them together with proper fillers. In this work, brazing temperature influences on microstructural, mechanical, and fractural properties were systemically studied for brazed joints after brazing the TiAl to the ZrB2-SiC with amorphous CuTiZrNi fillers. An optimized brazing condition was found as 1183 K for 1200s, yielding a high shear strength of 187 MPa. The joints were mainly consisted of AlCuTi, Ti2Al, (Ti,Zr)2(Cu,Ni), TiB, TiB2, TiCu Ti5Si3, and TiC phases. Brazing temperature substantially changed joint composites. It is found that lower temperatures lead to insufficient reaction and remained filler and higher ones to large stress-induced microcracks. Based on element diffusions, a formation mechanism of brazed joint was also proposed.