EXPERIMENTAL-STUDY AND MODELING OF COPPER PRECIPITATION UNDER ELECTRON-IRRADIATION IN DILUTE FECU BINARY-ALLOYS

In order to study the effect of the supersaturation of freely migratin g defects on the precipitation of copper in high residual copper press ure vessel steels under neutron irradiation FeCu (1.34, 0.30 and O.11 at.% Cu) model alloys were irradiated between 175 and 360 degrees C wi th high energy electrons. On-line electrical resistivity measurements and small angle neutron scattering (SANS) under magnetic field experim ents were carried out. The use of the latter method to get the chemica l composition of the precipitates is discussed. We show that the mecha nisms of precipitation are identical under electron irradiation and un der thermal aging. The sole effect of electron irradiation on the prec ipitation is to enhance the kinetics. A modelling of copper precipitat ion based on cluster dynamics is proposed. A comparison between our SA NS results obtained under electron irradiation and those under neutron irradiation published in the literature shows that the mechanisms of precipitation are very likely different with both kinds of particles.