Thermal shock behavior under deuterium plasma exposure of tungsten–tantalum alloys

Tungsten–tantalum (W-Ta) alloys for the application to fusion reactor divertor were developed to overcome the issues of W related to the low temperature brittleness, embrittlement by recrystallization, and embrittlement by neutron irradiation. In the present study, the response to cyclic thermal shock tests as well as the fundamental mechanical properties of W-3%Ta and pure W were investigated, which simulated a transient heat load event in the actual divertor environment. Because it was concerned that the effect of deuterium (D) plasma exposure might be much more pronounced in the Ta-alloyed materials, the thermal shock tests were performed under the background steady state D-plasma exposure. Based on the present study, W-3%Ta might be a competitive alloy system from the viewpoint of thermo-mechanical response in the actual divertor environment as well as the fundamental mechanical properties and resistance to recrystallization.