SANS STUDY OF STRUCTURAL-CHANGES IN IRRADIATED FECU DILUTE ALLOYS

Copper-rich precipitates formed in iron based dilute alloys by irradia tion or thermal ageing, have been investigated using small angle neutr on scattering (SANS). In particular, FeCu1.5% has been studied after e ither 2.5 MeV electron irradiations at 300-degrees-C or thermal ageing at 500-degrees-C. Size distribution, composition and number density o f the clusters were deduced from SANS data. In addition, microhardness measurements allowed to correlate precipitates configuration with all oys hardening. The precipitation mechanism looks the same for both kin ds of ageing, but irradiation induces an additional contribution to ha rdening. A linear correlation between duration of thermal ageing and i rradiation fluence can be established.