Compressive shape memory actuation response of stress-induced martensite aged Ni51Fe18Ga27Co4 single crystals

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2019-02, Vol.746, p.448-455
• Main Authors: Panchenko, E. Yu, Timofeeva, E.E., Chumlyakov, Yu.I., Osipovich, K.S., Tagiltsev, A.I., Gerstein, G., Maier, H.J.
• Format: Article
• Language: English
• Subjects: Actuation; Actuators; Aging; Aging (artificial); Chemical precipitation; Compressive properties; Crystal defects; Crystal growth; Crystal structure; High temperature; Hysteresis; Intermetallics; Martensite; Martensitic transformation; Martensitic transformations; Plastic deformation; Precipitates; Shape effects; Shape memory; Shape memory effect; Short range order; Single crystals; Stress-induced martensite aging; Superelasticity; Transformation temperature
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2019.01.004

In the present study, the effects of stress-induced martensite aging (SIM-aging) in twinned L10-martensite on the functional properties of [001]A-oriented Ni51Fe18Ga27Co4 (at%) single crystals were systematically investigated. SIM-aging of as-grown single crystals with γ-phase precipitates at TSIM = 448 K for 1 h, under a compressive stress σSIM of 700 MPa along the [001]A||[110]M-direction, leads to an increase in the martensitic transformation temperatures Ms and Af by 60( ± 3) K and induces a two-way shape memory effect with a reversible strain up to − 3.4( ± 0.3)%. Moreover, the SIM-aged crystals demonstrate a 1.5- to 2-fold decrease in the thermal and stress hysteresis as compared to the as-grown crystals. The SIM-aged crystals feature a narrow stress hysteresis and the high cyclic stability of superelasticity at elevated temperature up to 420 K. Thus, these materials are attractive for use as efficient high-temperature actuators. The physical reasons for martensite stabilization in the Ni51Fe18Ga27Co4 single crystals, such as the symmetry-conforming adaptation of the short-range order, the pinning of moving interfaces by defects, and the plastic deformation of γ-phase precipitates during SIM-aging, are discussed.