On the Effect of Hydrogen on the Low-Temperature Elastic and Anelastic Properties of Ni-Ti-Based Alloys

Abstract

Linear and non-linear internal friction and the effective Young’s modulus of a Ni50.8Ti49.2 alloy have been studied after different heat treatments, affecting hydrogen content, over wide ranges of temperatures (13–300 K) and strain amplitudes (10−7–10−4) at frequencies near 90 kHz. It has been shown that the contamination of the alloy by hydrogen strongly affects the internal friction and Young’s modulus of the martensitic phase. Presence of hydrogen gives rise to a non-relaxation internal friction maximum due to a competition of two different temperature-dependent processes. The temperature position and height of the maximum depend strongly on the hydrogen content. We conclude that many of the internal friction peaks, reported earlier for differently treated Ni-Ti-based alloys, had the same origin as the present maximum.

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

“…Similar behaviour of δ i and E was reported for the B19' martensitic phase of the Ni 50.8 Ti 49.2 alloy [6]. The characteristic pattern of δ i and E on the high-temperature side of the low-temperature IF maximum on heating/cooling was ascribed to a pinning/depinning stage due to increase/decrease of the hydrogen concentration in the core regions of twin boundaries [6]. The pinning/depinning stage was associated with redistribution of hydrogen between twin boundaries and other structural defects, such as bulk dislocations and/or grain boundaries [6].…”

“…Dehydrogenation treatment suppresses strongly the pinning stage provoking the increase of δ i and transformation of the well-defined low-temperature δ i (T) maximum into a plateau (or very smooth maximum at higher temperatures of 150-160 K). Similar behaviour of δ i and E was reported for the B19' martensitic phase of the Ni 50.8 Ti 49.2 alloy [6]. The characteristic pattern of δ i and E on the high-temperature side of the low-temperature IF maximum on heating/cooling was ascribed to a pinning/depinning stage due to increase/decrease of the hydrogen concentration in the core regions of twin boundaries [6].…”

“…Recently, we have studied the effect of hydrogen contamination during heat treatments on the low-temperature elastic and anelastic properties of a Ni 50. 8 Ti 49.2 alloy at ultrasonic frequencies, for which the '200 K' relaxation IF peak cannot be observed [6]. It has been shown that the hydrogen contamination gives rise to a non-relaxation internal IF maximum, whose temperature and height depend strongly on the hydrogen content.…”

“…It seems important to check whether the new hydrogen-related anelastic effect, reported in [6], is inherent only in the B19' martensitic phase, or it is common phenomenon for different martensitic phases of Ti-Ni-based alloys. The goal of the present work is to study the effect of hydrogen contamination on the elastic and anelastic properties of a Ti-Ni-based alloy with the R martensitic phase.…”

“…It has been shown that the hydrogen contamination gives rise to a non-relaxation internal IF maximum, whose temperature and height depend strongly on the hydrogen content. The IF maximum was interpreted as a pseudo-peak formed due to a competition of two different temperature-dependent processes affecting the hydrogen concentration in the core regions of twin boundaries [6].…”