Impact of viscous stress relaxation on the residual stress of a W-Cu joint component designed for the high-heat-flux targets of a nuclear fusion reactor

The production of a W-Cu divertor monoblock assembly shall be done using the HRP (Hot Radial Pressing) method. This process uses high temperatures and pressures to join the different components that compose the monoblock. Due to the large temperature transient that takes place during HRP and the different thermo-mechanical properties of tungsten and copper, stresses build up in the component. Previous studies have analyzed the stress build-up during HRP computationally and experimentally. However, no systematic analysis was done that considered viscoplastic effects in the relevant materials.

In this master thesis, the impact of viscous stress relaxation during HRP is further analyzed. The results will be used to support the interpretation of the experimental data already obtained and of future analysis. The thesis also presents an innovative method to simulate cutting processes, which are needed to compare simulated results with specific experimental analysis. In addition, the implication of the findings is discussed in terms of the component design, material testing and experimental stress measurements.