Evolution of interfacial structure of the joints between a tungsten-copper composite and austenitic stainless steel

Abstract

Joining of CuW70 composite and 0Cr18Ni9 stainless steel was successfully achieved at temperatures 1150 °C with durations from 15 to 90 min after adding a pure copper intermediate layer. Microstructure, phase composition and elemental distribution at the interfacial region were studied. The optimum joining interface with a dense microstructure was obtained at a joining temperature of 1150 °C with a duration of 60 min. Interdiffusion of atoms occurred at the interface between the tungsten-copper composite and stainless steel, resulting in formation of various compounds such as W0.6Cu0.4, Cu3.8Ni and Fe0.946Ni0.054. An iron chromium-rich layer was formed at the interface near the tungsten-copper composite side, and an island structure containing Cr, Cu, and Ni was formed near the stainless steel side.

Evaluation of Tungsten—Steel Solid-State Bonding: Options and the Role of CALPHAD to Screen Diffusion Bonding Interlayers

“…Residual stress was minimized in this configuration, and it was hypothesized that, during the cooling period, vanadium would transfer the residual stress from tungsten and eventually Cu would relieve the residual stress through plastic deformation. A Cu interlayer has also been used in diffusion bonds between the W-Cu composite and stainless steel at 1150 • C for different holding times [109]. It was found that the elements from the steel side exhibit intergranular diffusion while penetrating the Cu interlayer.…”

The Joining of Copper to Stainless Steel by Solid-State Welding Processes: A Review

“…The diverse nature of both materials is dominant during fusion welding processes. However, considerable effort has been made to join copper to stainless steel via fusion welding processes [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. Overall, it is safe to conclude that the metallurgy of copper to stainless steel joints must be the researcher’s focus when welding them with fusion welding processes.…”