Energy-Efficient Elastocaloric Cooling by Flexibly and Reversibly Transferring Interface in Magnetic Shape-Memory Alloys

Abstract

Elastocaloric cooling is currently under extensive study owing to its great potential to replace the conventional vapor-compression technique. In this work, by employing multiscale characterization approaches, including in situ neutron diffraction in a loading frame, in situ transmission electron microscopy observation at different temperatures, in situ synchrotron X-ray Laue microdiffraction, and high-resolution infrared thermal imaging, we have investigated the thermal and stress-induced martensitic transformation, the stability of superelastic behavior and the associated elastocaloric effect for a Heusler-type NiFeGaCo single crystal. On the basis of transformation from cubic austenite into monoclinic martensite with a flexibly and reversibly transferring interface, this unique single crystal exhibits a giant elastocaloric effect of 11 K and ultralow fatigue behavior during above 12 000 mechanical cycles. The numerical simulation shows that the NiFeGaCo alloy offers 18% energy saving potential and 70% cooling capacity enhancement potential compared to the conventional shape-memory nitinol alloy in a single-stage elastocaloric cooling system, making it a great candidate for energy-efficient air conditioner applications.

Enhancing the Elastocaloric Cooling Stability of NiFeGa Alloys via Introducing Pores

“…Single crystalline FMSMAs such as NiFeGa, NiFeGa–Co, and CoNiGa demonstrate superior reversibility and fatigue resistance over numerous stress cycles as compared with their bulk alloys . The single crystals are difficult to prepare and handle due to the severe segregation, low growth rate, and elevated cost .…”

Magnetocaloric and Elastocaloric Effects in All‐d‐Metal Ni37Co9Fe4Mn35Ti15 Magnetic Shape Memory Alloy

“…The characteristic temperatures ( M s , M f , A s , A f ) of the Ni 37 Co 9 Fe 4 Mn 35 Ti 15 determined from DSC curves are 293, 257, 268, 305 K, respectively. Compared with the result of M–T curves, the characteristic temperatures from DSC show some differences, which would probably attribute to the different sample sizes and heating and cooling rates . In addition, a thermal hysteresis can also be confirmed by the difference between M s and A f, implying a first‐order phase transition .…”

“…[26] At the same time, the substitution Co with Fe plays a critical role in tuning MT temperature due to the change in the number of valence electrons. [21,26] Figure 2b depicts the differential scanning calorimetry (DSC) heating and cooling curves at the range from 200 to 400 K for the all-d-metal Ni 37 [27] In addition, a thermal hysteresis can also be confirmed by the difference between M s and A f, implying a first-order phase transition. [28] The ΔS can be estimated by the relationship ΔS ¼ ΔH/T 0 , where T 0 is the equilibrium temperature defined as (M s þ A f )/2, and the ΔH is calculated as the areas of exothermic or endothermic peaks.…”

Characterization of caloric effects for magnetostructural transition materials: State-of-the-art and prospects

“…丹麦科技大学的Tušek等人 [52] 将红外热成像仪用于监 控主动回热式弹热制冷原型机在工作过程中各个部位 的温度变化. 借助红外热成像仪, 本研究团队 [53] 观测 到了磁性形状记忆合金Ni-Fe-Ga-Co在应力诱发马氏 体相变过程中马氏体板条的形核和扩展过程. 哈尔滨 工业大学张学习团队 [54] 利用电子背散射衍射技术结 合红外热成像仪的方法, 在同一Cu-Al-Mn薄带样品中 原位观测了不同取向晶粒的热效应.…”