Temperature dependence of the radiation damage microstructure in V-4Cr-4Ti neutron irradiated to low dose

Transmission electron microscopy (TEM) was performed on a V-4Cr-4Ti alloy irradiated to damage levels of 0.1-0.5 displacements per atom (dpa) at 110-505 degrees C. A high density of small faulted dislocation loops were observed at irradiation temperatures below 275 degrees C. These dislocation loops became unfaulted at temperatures above similar to 275 degrees C, and a high density of small Ti-rich defect clusters lying on {0 0 1} planes appeared along with the unfaulted loops at temperatures above 300 degrees C. Based on the TEM and tensile measurements, the dislocation barrier strengths of the faulted dislocation loops and {0 0 1} defect clusters are similar to 0.4-0.5 and 0.25, respectively. This indicates that both types of defects can be easily sheared by dislocations during deformation. Cleared dislocation channels were observed following tensile deformation in a specimen irradiated at 268 degrees C. (C) 1998 Published by Elsevier Science B.V. All rights reserved.