Effects of pre-strain on enhancement of hydrogen embrittlement induced by aging for pure Ta

Nakabachi, Kaito*; Yokoyama, Kenichi*; Ishijima, Yasuhiro ; Ueno, Fumiyoshi  ; Abe, Hitoshi 

To investigate the effects of strain and thermal aging on hydrogen embrittlement of Ta, tensile tests and internal friction measurements were carried out on cold rolled Ta after hydrogen charging and thermal aging. As a result, the internal friction increased with cold rolling. The internal friction was further increased by hydrogen charging. However, the internal friction of these specimens decreased after thermal aging. These results suggest that aging causes the annihilation or re-arrangement of defects or a change in the hydrogen trapping. In addition, the ductility of the hydrogen-charged and cold-rolled specimens decreased after thermal aging, suggesting that the change in hydrogen and defect state due to thermal aging affects the mechanical properties.