THE EVOLUTION OF COPPER PRECIPITATES IN BINARY FE-CU ALLOYS DURING AGING AND IRRADIATION

The evolution of copper precipitates in Fe-Cu alloys during thermal ag eing and irradiation, assuming the domination of Ostwald ripening, has been theoretically investigated. It is assumed that copper atoms diff use via a vacancy mechanism and copper clusters are homogeneously nucl eated. The diffusion coefficient and the binding energy of copper atom with a cluster as a function of cluster size, that fit satisfactorily the available experimental data for thermally aged Fe-Cu alloys, have been obtained. It was taken into account that the crystal lattice of copper precipitates changes from bcc at small sizes to fee at large on es via an intermediate martensitic stage. The results of calculations are in agreement with the observed evolution of copper precipitates in Fe-Cu alloys during thermal ageing and irradiation.