Microstructure and properties of W-Cu/CuCrZr/316L joint bonded by one-step HIP technique

Highlights: • W-Cu/CuCrZr/316L with Ni interlayer can be successfully joined by one-step HIP technique. • The microstructure of CuCrZr alloy are homogeneous with equiaxed grains and the mean grain size of CuCrZr alloy is around 42 μm. • A transition zone with two parts was found at the interface of CuCrZr/316L HIP joint. • A small number of micro-pores were found around the interface of CuCrZr/Ni joint. • A high impact toughness value of 104 ± 2 J/cm2 of CuCrZr/316L HIP joint was obtained as well. - Abstract: This work describes studies on the microstructure and properties of W-Cu/CuCrZr/316L joints bonded by one-step HIP technique. In the HIP process, both W-Cu/CuCrZr and CuCrZr/316L joints were connected simultaneously by diffusion bonding at 900 °C, 130 MPa for 2 h. Then for recovering the strength of CuCrZr alloy, heat-treatment process of solution annealing at 900 °C for 1 h which followed by water quench and aging treatment at 480 °C for 2 h were imposed on the HIPed module. After the heat treatment process, assessments on the microstructure, tensile test and Charpy impact test of the bonding joints were performed. Microstructural analysis showed that both the bonding joints were well welded and transition zones were observed along the interfaces of the joints. The microstructure of CuCrZr alloy was homogeneous with equiaxed grains and its mean grain size was around 42 μm. Mechanical test showed that the bonding strength of CuCrZr/316L joint was considerably high with an impact toughness value of 104 ± 2 J/cm².