Atom probe tomography of radiation-sensitive characterization KS-01 weld

The microstructure of a radiation-sensitive KS-01 test weld has been characterized by atom probe tomography. The levels of copper, manganese, nickel and chromium in this weld were amongst the highest of all the steels used in Western reactor pressure vessels. After neutron irradiation to a fluence of 0.8 x 10(23) nm(-2) (E > 1 MeV) at a temperature of 288 degreesC, this weld exhibited a large Charpy T-41j shift of 169 K, a large shift of the fracture toughness transition temperature of 160 K. a decrease in upper shelf energy from 118 to similar to78 J, and an increase in the yield strength from 600 to 826 MPa. However, the mechanical properties data conformed to the master curve. Atom probe tomography revealed a high number density (similar to3 x 10(24) m(-3)) Of Cu-, Mn-, Ni-, Si- and P-enriched precipitates and a lower number density (similar to1 x 10(23) m(-3)) of P clusters. (C) 2003 Elsevier B.V. All rights reserved.