In situ synthesis and bonding of TiTiAlTiC/Ni functionally graded materials by field-activated pressure-assisted synthesis process

Employing reactive synthesis and consolidation and using elemental powders as reactants, TiC/Ni cermets were formed and bonded to Ti substrates in one step by a field-activated method. Microstructural observations and EDS analyses revealed well-formed, crack-free bonds between the layers. Bonding between the TiC/Ni cermet and the Ti substrate was facilitated by the formation of TiAl as an intermediate layer, which also formed from the elements during the on-step process.Shear strength and thermal shock evaluations were made on the resulting samples. The diffusion-bonded interface has a shear resistance of as high as 70.98 MPa and has a good thermal shock resistance. Crack propagation observations indicate high interface strength. The interface between Ti and TiAl has a higher bonding strength than that between the TiC/Ni cermet and TiAl.

► An advanced bonding of cermet to metal was carried out by PAPAS process. ► In situ synthesis of TiC/Ni and bonding to Ti were accomplished in one step. ► TiAl was used as intermediate layer of bonding. ► Heat produced by the formation of TiAl from element powder was the key of bonding. ► The diffusion-bonded interface has higher shear and thermal shock resistance.