PREDICTION OF CREEP-RUPTURE PROPERTIES FOR AUSTENITIC STEELS UNDERGONE NEUTRON IRRADIATION

The paper presents the physical and mechanical model that allows predicting fracture of materials subjected to neutron irradiation under creep. The model is based on the equations of void nucleation and growth on grain boundaries that were proposed earlier. The equations are developed for the case of neutron irradiation of a material. The constitutive equations describing viscoplastic deformation of a material with regard to void evolution are formulated. The criterion of microplastic collapse of a unit cell is used as a fracture criterion. The creep-rupture strength and ductility of austenitic materials in the initial and irradiated conditions with different neutron flux levels are predicted on the basis of the model. The calculated results are compared with the available experimental data.