Autogeneous pressure-assisted interlayer-free diffusion bonding of Ti(C,N)-based cermet and steel

A diffusion bonding technique free of interlayer and external pressure was introduced, and the bonding pressure was generated due to linear shrinkage of Ti(C,N)-based cermet and thermal expansion of steel. The Ti, Ni, Fe concentrations across the joint evolved gradually and binder-riched surface layer, Fe-Co bonded cermet layer and austenite layer formed successively. The tensile residual stress decreased and the stress concentration region transferred away from the cermet side to the steel side. Diffusion bonding was combined with the liquid phase sintering process, and the cermet substrate need not to be heated twice. Compared with traditional method, the joint strength is improved due to graded microstructure, residual stress decrease and bonding process simplification.