Micromechanical and microstructural effects of high dose helium implantation in single crystal vanadium

Vanadium alloys are candidates for fusion applications. helium and radiation effects in vanadium and its alloy is studied to understand the performance of these materials in a radiation environment and to bring insight into the effects of body centered cubic alloys in general. In this work we performed low energy ion beam implantation to achieve blistering and surface near effects and understand the blister failure mode and mechanical property changes due to radiation damage and helium content. Micro-compression testing via a novel procedure as well as 4D STEM were conducted. It was found that helium bubbles connect and generate a critical crack. The helium bubbles cause a high yield strength and large residual stress. The subsequent blistering causes severe strain in the irradiated material and the deformed material rotates its crystal.