Protium absorption properties of Ti–V–Cr–Mn alloys with a b.c.c. structure

Abstract

The protium absorption–desorption properties of Ti–V–Cr–Mn alloys were studied by varying the contents of Mn, Ti and V in the alloys. It was found that Mn addition of <10 at% was effective in improving the slope of the plateau region without any reduction of the protium absorption–desorption capacity. For Ti–V–Cr–Mn alloys, the α-Ti phase, which does not contribute to the protium storage capacity, appeared along grain boundaries during heat treatment. The formation of the α-Ti phase was found to be suppressed by reducing the Ti content and increasing the V content. By inhibiting the appearance of the α-Ti phase along the grain boundary, the protium absorption–desorption capacity of Ti– xV–Cr–Mn ( x=45, 55; Ti/Cr/Mn=24:31:10) heat-treated alloys exhibited 2.7 mass% H, the highest value reported so far.