Prediction of radiation-induced yield stress increment in austenitic stainless steels by using a computational approach

A computational model is presented for quantitatively estimating an increase in yield strength due to neutron irradiation by combining a cluster dynamics model and a dislocation dynamics simulation. The former calculates the concentration of point defects and defect clusters by taking into account the diffusive encounters between the point defects and the extended defects. The latter simulates the motion of dislocations in a matrix containing defect clusters. In determining the input parameters for the cluster dynamics calculations, we have obtained the primary damage parameters such as the cascade efficiency and the clustering fractions by using molecular dynamics simulations. We computed the increases in the yield strength of the austenitic stainless steels by using dislocation dynamics with the density and size distribution of radiation defects, which were obtained from the cluster dynamics calculations. The results suggest that a computational method can be a convenient tool for estimating radiation-induced hardening.