Large and reversible elastocaloric effect induced by low stress in a Ga-doped Ni-Mn-Ti alloy
Year: 2024
Type: article
Abstract: The Solid-state cooling based on caloric effects is considered a potential alternative to conventional refrigeration technology, which uses ozone-depleting gases. Several shape memory alloys have attracted attention for solid-state cooling since they present a high reversibility of the caloric effect, which depends mainly on thermal hysteresis and sensitivity to the applied field. In the present work, a study substitution of Mn by Ga in the Ni 50 Mn 34 Ti 16 alloy led to diminished thermal hysteresis in the martensitic transformation by 9 K. The elastocaloric effect, thermal and microstructure properties of a polycrystalline Ni 50 Mn 32 Ti 16 Ga 2 alloy have been characterized. The elastocaloric effect was obtained indirectly from the length change as a function of temperature at constant stress. An isothermal entropy change (Δ S ISO ) of 23.0 J kg −1 K −1 during heating and 22.0 J kg −1 K −1 during cooling was observed for applied stress of 160 MPa. In addition, the Δ S ISO is reversible for a temperature span between 287 and 319 K, reaching a maximum of 20.5 J kg −1 K −1 at 299 K. The thermal hysteresis changed slightly while the applied stress increased up to 160 MPa since the sensitivity of the martensitic transformation temperatures to stress was 0.150 K/MPa during cooling and 0.160 K/MPa during heating. The X-ray diffraction analysis revealed a mixture of B2-type cubic austenite, 5M modulated martensite, and a second intermetallic phase identified as Ni 3 Ti. All these results were obtained around room temperature.
Source: Results in Physics
Authors: L.A. Ascencio de la Cruz, M. López-Medina, D.E. Soto-Parra, D. Ríos-Jara, J.P. Camarillo-Garcia, H. Flores-Zúñiga
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,690
OpenAlex ID: W4403352862