Effect of the Obstacles for Dislocation Motion on the Radiation Embrittlement of Fusion Reactor Materials

Embrittlement of nuclear reactor materials is regarded as one of the most important problems in radiation physics. One of the widespread approaches relates the embrittlement of bcc materials (ferritic/martensitic steels, vanadium alloys etc.) to impurities that can precipitate under irradiation. Fracture of iron as wll as modern structural materials occurs through crack nucleation and growth. Precipitation can affect crack growth directly via elastic interaction and indirectly through locking the dislocation motion. The primary topic of the research is the effect of obstacles for dislocation motion on the plastic zone formation, the crack blunting and shielding. Features of the plastic zone (size, dislocation density etc.) are investigated. Reduction of stress intensity factor vs. size, volume fraction and distribution of precipitates is evaluated. Dependence of embrittlement of structural reactor materials on the concentration of precipitates is established.