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

• Published in: Journal of alloys and compounds 2018-06, Vol.751, p.359-363
• Main Authors: Baturin, Anatoly, Lotkov, Aleksander, Grishkov, Victor, Rodionov, Ivan, Kudiiarov, Victor
• Format: Article
• Language: English
• Subjects: Aging; Aging (metallurgy); Differential scanning calorimetry; DSC; Electrolytes; Hydrogen; Hydrogen storage; Hydrogenation; Intermetallic compounds; Martensite; Martensite transformation; Martensitic transformations; Measurement methods; Nanocrystalline and coarse-grained structure; Nanocrystals; Nickel base alloys; Nickel compounds; Phase transitions; Shape memory alloys; TiNi alloy; Titanium compounds
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.04.045

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. •Hydrogen effect on the martensitic transformation in Ni-rich TiNi alloy are studied.•Wire samples had a nanocrystalline and coarse-grained structure.•At the ageing at room temperature the suppression of MT B2–B19′ or R–B19′ are observed.•At the ageing a widening of the premartensitic temperature range are observed.•The observed changes are due to the diffusion redistribution of hydrogen.