Small-scale functional fatigue of a Ni-Mn-Ga Heusler alloy

Functional fatigue of shape-memory alloys is a considerable threat to the reliable service of actuation devices. Here, we demonstrate the essentially degradation-free cyclic phase-transformation behavior of Ni-Mn-Ga microcrystals up to one million stress-driven superelastic cycles. Cyclic dissipatio...

Full description

Saved in:
Bibliographic Details
Published in:Acta materialia 2024-08, Vol.274, p.119988, Article 119988
Main Authors: Fareed, Adnan, Rosalie, Julian M., Kar, Satyakam, Fähler, Sebastian, Maaß, Robert
Format: Article
Language:English
Subjects:
Functional fatigue
Ni-Mn-Ga
Shape-memory alloys
Superelasticity
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Functional fatigue of shape-memory alloys is a considerable threat to the reliable service of actuation devices. Here, we demonstrate the essentially degradation-free cyclic phase-transformation behavior of Ni-Mn-Ga microcrystals up to one million stress-driven superelastic cycles. Cyclic dissipation amounts to about 1/5 of the bulk counterpart and remains unaffected during cycling, even after the introduction of dislocation structures via plastic straining. Plastic yielding and the transformation stress largely exceed the known bulk values. However, the transformation-stress is found to depend on plastic pre-straining, which suggests that the size-affected transformation stress is sensitive to the initial defect structure and that it can be tuned by a targeted introduction of dislocations. These findings demonstrate the high suitability of Ni-Mn-Ga as a robust shape-memory alloy in small-scale functional device engineering. [Display omitted]
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2024.119988