Relationship between Low Temperature Toughness and Microstructure in Low Activation Fe-Cr-Mn (W, V) Steel for Fusion Reactors

Fe-Cr-Mn (W, V) austenite steel was researched in order to supply a theory base for the first wall materials of fusion reactors.Experiments included vacuum melting, forging, annealing, solution treatment, Charpy impact tests and microstructure observation. The results show that the imped value decreases with the test temperature decreasing. In this system, there is ductile/brittle transition. The mechanism of this decrease of the impact value is considered to be due to γ→ε transformation in sub-stable austenite steel and stopping overlapping sacking fault by grain boundaries in stable austenite steel.