Influence of fast neutron irradiation on dynamic fracture toughness of some steels

Neutron irradiation has an adverse effect on the fracture properties of reactor pressure vessel steels. Much has been written in recent years about neutron embrittlement of materials that are used in the nuclear industry. These papers have clearly demonstrated trends in embrittlement with neutron exposure which involve a large increase in the brittle-to-ductile transition temperature and a decrease in the fracture toughness. In this paper, within the framework of dynamic fracture mechanics, the values of KId corresponding to high loading rates K ≅ 107 MPa m1/2·s-1 are determined by using HPB the (Hopkinson pressure bar) technique modified for fracture testing of neutron-irradiated steels