Effect of grain boundary direction on blistering in deuterium-exposed tungsten materials: Parallel grain boundary versus perpendicular grain boundary
Mi Liu, Long Cheng, Yue Yuan, Shiwei Wang, Hao Yin, Ting Wang, Guang–Nan Luo, Xiang Liu, Guang‐Hong Lu
Abstract
Abstract The effect of grain boundary (GB) direction with respect to the exposed surface on blistering in tungsten (W) is studied. Four types of W materials were used in this work and classified according to GB directions: one with GBs parallel to the exposed surface (parallel GBs) and the other with GBs perpendicular to the exposed surface (perpendicular GBs). After exposure to high flux deuterium plasmas, blisters were observed and found to be related to GBs in all types of materials. It is found that large-size blisters were originated from parallel GBs rather than perpendicular GBs. Blisters were supposed to grow faster in parallel GBs than in perpendicular GBs. Moreover, the exfoliation of blister caps was observed in the materials with parallel GBs but not in that with perpendicular GBs. This study provides a new insight into the role of GB direction on blistering.