Manufacturing and testing of flat type W/Cu/CuCrZr mock-ups by HIP process with PVD coating

Abstract The development of W/Cu/CuCrZr mock-ups by hot isostatic pressing (HIP) bonding technology is in progress for the application to tungsten divertor. In HIP process, physical vapor deposition (PVD) method was applied for interlayer coating of high purity nickel (Ni) and copper (Cu). Interlayer coatings were selected to enhance diffusion between tungsten (W) and oxygen free high conductivity copper (OFHC-Cu) interlayer during the HIP bonding process. The Ni and Cu were deposited by different thicknesses on tungsten surface with roughness of 6Z and 0.8Z. HIP technology is employed with two kinds of processing conditions: 60 MPa, 600 ℃ and 70 MPa, 700 ℃. The interlayer of samples are observed by FE-SEM and EDS and subjected to shear test and heat flux test. There is no significant difference in shear strength due to PVD coating thickness. But the shear strength of samples fabricated by 70 MPa and 700 ℃ HIP condition is higher than those fabricated by 60 MPa and 600 ℃ condition. Heat flux tests were performed to compare the thermal conductance through the bonded layer and thermal fatigue behavior of the samples as a preliminary test of bonding quality. All these results were analyzed systematically to find the optimum fabrication conditions in the HIP bonding of W/Cu/CuCrZr.