Gas Porosity Formation in the Vanadium Alloys V–W, V–TA, V–ZR During Helium-Atom Irradiation at 650 °C

Transmission electron microscopy is used to study the influence of alloying vanadium with tungsten, tantalum, and zirconium on the natural mechanisms of helium porosity formation and gas swelling during 40 keV He+ ion irradiation to dose 5 · 1020 m–2 at 650 °C. The formation of a bubble microstructure and gas swelling of vanadium alloys depends on the chemical and impurity composition of the irradiated materials. It was determined that in vanadium large facetted helium pores form and high gas swelling is observed, and in addition the swelling is significantly greater in high-purity vanadium. Alloying with tungsten increases swelling while tantalum has virtually no effect and zirconium and its analog titanium greatly reduce swelling. A definite correlation is observed between swelling and the number of electrons participating in the interatomic bond in alloys.