Effect of aluminum on solubility and β phase stability of vanadium–hydrogen system

Effect of aluminum on hydrogen solubility and β phase stability of vanadium–hydrogen system have been investigated employing thermo gravimetric (TG), differential thermal analysis (DTA) and X-ray diffraction technique. Vanadium aluminum alloys have been prepared by aluminothermy process followed by electron beam refining and vacuum arc melting. High purity vanadium is used for the comparative study. The hydrogen solubility decreases with aluminum content and with temperature. Substantial variation of hydrogen desorption mechanism from α as well as from β phase was observed due to the aluminum content. Desorption kinetics and modification of phase stability are the two possible reasons for the observed phenomenon.

► Aluminum additions lower the hydrogen solubility in vanadium.
► The solubility of hydrogen in V–Al alloys (V (α) + β (V2H) phase mixture) decreases with increased temperature.
► Aluminum additions to vanadium reduce the hydrogen desorption temperature.
► With temperature hydrogen solubility decreases in the coexisting alpha and beta phase.