Study of the micromechanical behaviour of irradiated V-4Cr-4Ti by in-situ microcolumn compression.

• Dislocation loops are the main defect after irradiation of V-4Cr-4Ti. • Edge dislocations were found in the lattice images contributing to stress strengthening. • The irradiated samples exhibited different deformation behavior. • Aggregation of dislocation loops causes difficulty in activate slip system resulting in increased stresses. V-4Cr-4Ti was irradiated with V self-ions, and thermal properties, microstructure evolution and mechanical behaviour were analysed to elucidate the deformation mechanism of irradiation-induced defects. The results of the thermal analysis showed that no precipitates were produced during the irradiation process. Dislocation loops were the main defects after irradiation, and edge dislocations were found through lattice images with a lattice mismatch of 12.5%. The yield stress of irradiated samples increased, which may be due to interactions between dislocations during the deformation process. The deformation mechanism was discussed based on the Schmidt factor. [ABSTRACT FROM AUTHOR]