Analysis of CuCrZr/316L(N) bimetallic joint with and without nickel interlayer for plasma-facing components

The work considers the CuCrZr/316L(N) bimetallic joint, which is obtained by diffusion bonding using hot isostatic pressing (HIP) and is a design element of the plasma-facing components (PFC) of a thermonuclear reactor. A comparative analysis of the specified bimetallic joint with a nickel interlayer obtained by different methods and without it has been carried out. A study of the structure and elemental composition of the bimetallic joint was made, where the brittle zirconium phases were identified in the interface zone for all the considered variants. The results of microhardness testing are obtained, demonstrating the presence of a sharp transition of hardness values by more than two times at the interface of two metals. A series of rupture tests of the bimetallic samples was carried out and almost identical values of the rupture stress were obtained for all the considered bimetallic joint variants. The fracture of the samples during the testing at temperatures up to 150°C occurred on the base metal and at higher temperatures – on the bimetallic joint.