Tungsten/steel diffusion bonding using Cu/W–Ni/Ni multi-interlayer

Diffusion bonding between tungsten and 0Cr13Al stainless steel using a Cu/90W–10Ni powder mixtures/Ni multi-interlayer was carried out in vacuum at 1150 °C with a pressure of 5 MPa for 60 min. The microstructures, composition distribution and fracture characteristics of the joint were studied by SEM and EDS. Joint properties were evaluated by shear experiments and thermal shock tests. The results showed that the joints comprised tungsten/Cu–Ni sub-layer/W–Ni composites sub-layer/Ni sub-layer/0Cr13Al stainless steel. The W–Ni composites sub-layer with a homogeneous and dense microstructure was formed by solid phase sintering of 90W–10Ni powder mixtures. Sound bonding between tungsten base material and W–Ni composites sub-layer was realized based on transient liquid phase (TLP) diffusion bonding mechanism. Joints fractured at bonding zone of W–Ni composites sub-layer and Ni sub-layer during shear testing, and the average strength was 256 MPa. Thermal shock tests showed that joints could withstood 60 thermal cycles quenching from 700 °C to room temperature.