Effect of Hydrogen on the Elastic and Anelastic Properties of the R Phase in Ti50Ni46.1Fe3.9 Alloy

• Published in: Metals (Basel ) Vol. 7; no. 11; p. 493
• Main Authors: Sapozhnikov, Konstantin, Torrens-Serra, Joan, Cesari, Eduard, Van Humbeeck, Jan, Kustov, Sergey
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 10-11-2017
• Subjects: acoustic properties; Anelasticity; Defects; Dehydrogenation; Elastic properties; Friction; Hydrogen; Hydrogen storage; Internal friction; lattice defects; Modulus of elasticity; shape memory alloy; Temperature; Temperature dependence; Titanium base alloys; Twin boundaries
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met7110493

The linear and non-linear internal friction, effective Young’s modulus, and amplitude-dependent modulus defect of a Ti50Ni46.1Fe3.9 alloy have been studied after different heat treatments, affecting hydrogen content, at temperatures of 13-300 K, and frequencies near 90 kHz. It has been shown that the contamination of the alloy by hydrogen gives rise to an internal friction maximum in the R martensitic phase and a complicated pinning stage in the temperature dependence of the effective Young’s modulus at temperatures corresponding to the high-temperature side of the maximum. Dehydrogenation of the H-contaminated alloy transforms the internal friction maximum into a plateau and minimizes the pinning stage. The internal friction maximum is associated with a competition of two different temperature-dependent processes affecting the hydrogen concentration in the core regions of twin boundaries. The amplitude-dependent anelasticity of the R phase is also very sensitive to hydrogen content, its temperature dependence reflects the evolution of extended hydrogen atmospheres near twin boundaries.