その場小型パンチ試験による 5 族水素透過膜の延性-脆性遷移水素濃度(DBTC)解析

抄録

  For the group 5 metals, even in an ambient hydrogen atmosphere (pressure), a large amount of hydrogen dissolves into them and severe hydrogen embrittlement occurs. This means that there is a large barrier to the practical application of these metals as a hydrogen permeation membrane for hydrogen separation and purification. In this study, we have found that a ductile-to-brittle transition occurs for the niobium (Nb) or vanadium (V) metals as a function of the “hydrogen concentration”, by using a special setup of the in-situ small punch (SP) testing apparatus equipped with a gas-flow system. This paper deals with a definition for the discovered phenomenon that group 5 metals have hydrogen concentration which changes from ductile-to-brittle fracture (DBTC: Ductile-to-Brittle Transition hydrogen Concentration). The grain size and the alloying effects of tungsten (W) and molybdenum (Mo) on the DBTC of Nb or V have also been clarified. Using this advanced approach, the importance of the DBTC analyses is described on the design of group 5 metal based hydrogen permeation membranes.