Effect of hydrogen redistribution during aging on the structure and phase state of nanocrystalline and coarse-grained TiNi alloys

The report presents research data showing how the phase state and transition temperatures in hydrogenated nanocrystalline and coarse-grained TiNi alloys are influenced by hydrogen redistribution on their aging at room temperature. The research methods include four-point measurements of resistivity as a function of temperature and differential scanning calorimetry at 173-373 K. The results demonstrate that hydrogen diffusion in the material bulk provides gradual suppression of B2→B19′ and R→B19′ transformations and that the temperature of B2→R transformation is hardy sensitive to hydrogen. Also presented is an analysis of the mechanism by which hydrogen acts on the temperatures and sequence of martensite transformations.