Low-temperature superelasticity and elastocaloric effect in textured Ni–Mn–Ga–Cu shape memory alloys

Long-Term Stable Elastocaloric Effect in a Heusler-Type Co51V33Ga16 Polycrystalline Alloy

“…Consistent with the strain rate dependence of Δσ hys , the Δ W rapidly increases with increasing strain rate and gradually stabilizes with the strain rate higher than 1.7 × 10 –2 s –1 . Since the stress hysteresis originates from the interfacial friction of austenite/martensite and martensitic variants, the increase of Δσ hys renders the enhanced irreversible energy losses, thereby weakening the fatigue life …”

“…Since the stress hysteresis originates from the interfacial friction of austenite/martensite and martensitic variants, the increase of Δσ hys renders the enhanced irreversible energy losses, thereby weakening the fatigue life. 38 From the compressive superelastic stress−strain curves at various strain levels under the strain rate of 1.1 × 10 −2 s −1 (Figure 6a), it is shown that the stress plateau related to the reverse martensitic transformation is gradually decreased with the increase of compressive strain, resulting in the broadening in the hysteresis loop. As shown in the inset of the Figure 6b, the ΔW is also dependent on the strain level, increasing from 0.1 J m −3 under the compressive strain of 1.5% to 2.3 J m −3 under 4%.…”

Elastocaloric Properties of Polycrystalline Samples of NiMnGaCu Ferromagnetic Shape Memory Alloy under Compression: Effect of Improvement of Thermoelastic Martensitic Transformation

“…There was no evaluation of the real thermodynamic efficiency in the one cycle where heat transfer was included. However, it was a first indication that can give some information about microstructure optimization, and it was not so far from other values obtained in the literature [ 18 ]. The tuning of the ratio between the heat involved and the mechanical work associated with the mechanical hysteresis is the principal way of obtaining a more promising material from the elastocaloric point of view.…”

“…The superelastic behaviour and the elastocaloric effect of [001]-textured polycrystalline Ni 50 Mn 23 Ga 25 Cu 2 were investigated by Guo et al below room temperature [ 18 ]. The authors found a good balance between the adiabatic temperature change ( Δ T ad ) and the coefficient of performance ( COP mat ), suggesting that this material can be a promising candidate for low-temperature elastocaloric refrigeration.…”

Large Elastocaloric Effect in Fe‐Doped Co–Fe–V–Ga Shape Memory Alloys

“…[3,6,7] According to different external fields, the thermal effects from the modified solid refrigeration systems were attributed to the magnetocaloric effect (magnetic field), electrocaloric effect (electric field), barocaloric effect (hydrostatic pressure field), and elastocaloric effect (eCE) (uniaxial stress field). [2,[8][9][10] The eCE utilizes the phase transformation latent heat when external uniaxial stress is rapidly applied or removed to realize heating or refrigeration. [11][12][13][14] This enables one to achieve up to %75% of the energy efficiencies in solid-state cooling, making it one of the most promising non-vapor compression cooling technologies according to the US Department of Energy.…”