Structure, Phase Composition, and Hydrogen Absorption Properties of Multiphase Alloys of Ti–Zr–Mn–V System Alloyed with Holmium

Abstract

The effect of an RE element (holmium) on the phase composition, microstructure, and hydrogen absorption properties of multiphase alloys of the Ti-Zr-Mn-V system comprised of the Laves phase and b.c.c. solid solution is studied. It is found out that holmium practically does not dissolve in the initial phases of the alloy, and it forms a new phase in combination with oxygen, holmium oxide. The crystallites of holmium oxide precipitate on the surface of the crystallites of the Laves phase and b.c.c. solid solution. It is determined that the formation of the new phase leads to a change in the structure of the initial alloys from eutectic to multiphase, that causes an increase in the grain surface area of the phase constituents. It is shown that the crystallites of holmium oxide raise the temperatures at which hydrogen absorption and desorption occur, as well as decrease the hydrogen capacity of the alloy.