Elastocaloric and magnetocaloric effects in Ni-Mn-Sn(Cu) shape-memory alloy

Abstract

We have studied magnetocaloric and elastocaloric properties of a Ni-Mn-Sn(Cu) metamagnetic shape-memory alloy undergoing a magneto-structural transition (martensitic type) close to room temperature. Changes of entropy have been induced by isothermally applying both mechanical (uniaxial stress) and magnetic fields. These entropy changes have been, respectively, estimated from dilatometric measurements giving the length of the sample as a function of temperature at selected applied forces and magnetic fields and from magnetization measurements as a function of temperature at selected applied magnetic fields. Our results indicate that the elastocaloric effect is conventional and occurs in two steps which reflect the interplay between the martensitic and the incipient magnetic transitions. By contrast, the magnetocaloric effect is inverse and occurs in a single step that encompasses the effect arising from both transitions.

Orientation Dependence of the Elastocaloric Effect in Ni54Fe19Ga27 Ferromagnetic Shape Memory Alloy

“…Although the giant ECE has been known of for some time, there is a lack of available scientific data needed for the successful design and implementation, or optimization, of multicomponent ECE systems. SMAs have been studied for their giant ECE via stress‐induced martensitic transformation and include NiTi, NiFeGa, CuZnAl, NiMnGaFe, NiMnGaCo, NiMnSn(Cu), and NiCoMnIn . These alloys have been reported to exhibit stress‐induced isothermal entropy changes of around 30, 10–20, 22.8, 5.5, 2.5, 1.75, and 5.5 J kg −1 K −1 under the stresses of 500, 150, 105, 9.3, 9.8, 5.24, and 75 MPa, respectively.…”

Large and reversible elastocaloric effect in dual-phase Ni54Fe19Ga27 superelastic alloys

“…[1][2][3] Recently, elastocaloric effect (eCE) primarily originated from lattice vibration or softening entropy changes has been reported in Cu-Zn-Al, 4,5 Ti-Ni-(Cu), [6][7][8] FePd, 9,10 and Ni-Mn-based shape memory alloys (SMAs). [11][12][13] In addition, some demonstration setups have been built to analysis the influence of various elastocaloric refrigerants, sample geometries, as well as operating conditions on the process functions. 14,15 Furthermore, an assessment report in 2014 from the U.S. Department of Energy on the alternative cooling technologies evaluated that the eCE cooling ranked the largest potential among all alternative non-vapor-compression technologies.…”

Shape memory behavior of Ni-Fe-Ga and Ni-Mn-Sn ribbons

“…Recently another interesting mechanic-caloric effect, the elastocaloric effect (ECE), has attracted more attention into these systems. ECE consists in the isothermal entropy change or adiabatic temperature change within a material as a consequence of applying/removing of a stress, and in some bulk alloys like Cu-Zn-Al, Ni-Mn-SbCo, and Ni-Mn-Sn(Cu) a notable ECE has been observed [2][3][4][5]. It is a well-known fact that thermo-mechanical characterization is the principal way to investigate the actuating properties of these materials and to indicate the possibility of an optimization of their functional performance.…”

“…It should be emphasized that magnetically ordered SMAs, called magnetic shape memory materials, exhibit excellent ordinary shape memory characteristics (e.g., [2][3][4][5]). In this work, melt spun ribbons of the ferromagnetic SMA, Ni 55 Fe 16 Ga 29 (at.%), and metamagnetic SMA, Ni 50 Mn 40 Sn 10 (at.%), have been prepared and characterized under reduced values of the external stress preferable for ECE applications.…”