Experimentally correlating thermal hysteresis and phase compatibility in multifunctional Heusler alloys
Experimentally correlating thermal hysteresis and phase compatibility in multifunctional Heusler alloys
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DOI：
10.1103/physrevmaterials.4.114403
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
Alberto A. Mendoncca;L. Ghivelder;P. L. Bernardo;H. Gu;Richard D. James;L. F. Cohen;Angelo M. Gomes
中科院分区：
文献类型：
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作者：
Alberto A. Mendoncca;L. Ghivelder;P. L. Bernardo;H. Gu;Richard D. James;L. F. Cohen;Angelo M. Gomes
热滞后被认为是一阶相变磁热和铁磁形状记忆材料循环应用的主要缺点之一。因此，面临的挑战是制定策略，提高过渡中所涉及的相之间的兼容性，并研究其对热滞后的影响。为此，我们探讨了Ni 2 Mn 1-xCuxGa0.84Al0.16 Heusler合金的热，结构和磁性。当化合物中的铜含量从x = 0.10变化到x = 0.25时，合金的热滞后减少约60%，最小滞后宽度为6 K。我们应用马氏体的几何非线性理论来解决相兼容性，量化的参数ε 2，中间特征值的转变拉伸张量，并发现，滞后的最小值与奥氏体和马氏体相之间的更好的晶体学兼容性（ε 2接近1）。此外，我们表明，谷状的滞后特性中发现的Ni 2 Mn 1-xCuxGa0.84Al0.16化合物是存在于其他几种合金在文献中。这些结果为理解和掌握多功能Heusler合金的相相容性并最终实现低热滞提供了新的途径。
Thermal hysteresis is recognized as one of the main drawbacks for cyclical applications of magnetocaloric and ferromagnetic shape memory materials with first order transformations. As such, the challenge is to develop strategies that improve the compatibility between the phases involved in the transitions and study its influence on thermal hysteresis. With this purpose, we explore the thermal, structural and magnetic properties of the Ni2Mn1-xCuxGa0.84Al0.16 Heusler alloys. The alloys present a thermal hysteresis reduction of ~60% when the Cu content in the compound varies from x = 0.10 to x = 0.25, with a minimum hysteresis width of 6 K being achieved. We applied the geometric non-linear theory of martensite to address the phase compatibility, quantified by the parameter lambda2, the middle eigenvalue of the transformation stretch tensor, and found that the minimum of hysteresis is associated with a better crystallographic compatibility (lambda2 closer to 1) between the austenite and martensite phases. In addition, we show that the valley-like properties of hysteresis found in the Ni2Mn1-xCuxGa0.84Al0.16 compounds is present in several other alloys in the literature. These results provide new pathways to understand as well as to masters the phase compatibility and ultimately achieve a low thermal hysteresis in multifunctional Heusler alloys.