Clustering of Point Defects Under Electron Irradiation in Dilute Iron Alloys and an Iron Manganese Nickel Alloy

Abstract

AbstractIn low copper steels for nuclear reactor pressure vessel, point defect clustering seems to play an important role in hardening. In order to study the hardening component which results from the clustering of freely migrating point defects, we irradiated, in a high voltage electron microscope, Fe, the alloys Fe0.13%Cu and Fe0.014%P, alloys and the alloy Fel.5%Mn0.8%Ni0.1%Cu0.01%P, the composition of which is close to the matrix of pressure vessel steels. We studied the nucleation of dislocation loops and their growth velocity. We find out that copper and phosphorus have no effect on the vacancy migration energy but that this parameter decreased significantly in the complex alloy. The main point is certainly that loops are nucleated in the complex model alloy up to 500°C while no loop appears above 300°C in Fe and in FeCu. FeP shows an intermediate behavior.