Influence of high-temperature ion irradiation on microstructures of the deformed and heat-treated V-4Cr-4Ti alloy

Abstract

As one of candidate structural materials for future fusion reactors, vanadium alloy has been widely studied in recent decades. In the present investigation, an attempt was made to determine the influence of high energy ions irradiation on the microstructures of V-4Cr-4Ti alloy which had been subjected to aging, cold deformation and heat-treatment. To achieve the aim, aging and cold reduction were carried out, followed by isothermal heat-treatment at 1100°C for different time. Hardness measurement, optical and electron microscopies were employed to characterize microstructures of the samples. It was found that Ti-rich precipitates coherent to the matrix occur during aging. In the deformed samples, dislocation movement are inhibited by the precipitates, from which dislocation-precipitates interaction are formed. After 550keV Fe10+ irradiation at 500°C, a lot of voids, dislocation loops and fine precipitates occur in the alloy. The orientation of irradiation induced precipitates (Vanadium Carbide) is random. The sizes of voids are smaller in the annealed samples. The dislocation networks in the aged sample can remain partially after irradiation, due to pinning effect of precipitates formed during aging.