Zheng Zhigang, Huang Pengyan, Chen Xinglin, Wang Hongyu, Da Shan, Wang Gang, Qiu Zhaoguo, Zeng Dechang
School of Materials Science & Engineering, South China University of Technology, Guangzhou 510640, China.
Yangjiang Branch, Guangdong Laboratory Materials Science and Technology Yangjing Advanced Alloys Laboratory, Yangjiang 529599, China.
Entropy (Basel). 2024 Sep 19;26(9):799. doi: 10.3390/e26090799.
In order to improve the magnetocaloric properties of MnNiSi-based alloys, a new type of high-entropy magnetocaloric alloy was constructed. In this work, MnNiSiFeCoGe ( = 0.4, 0.45, and 0.5) are found to exhibit magnetostructural first-order phase transitions from high-temperature NiIn-type phases to low-temperature TiNiSi-type phases so that the alloys can achieve giant magnetocaloric effects. We investigate why / (/) gradually increases upon Co substitution, while phase transition temperature () and isothermal magnetic entropy change (Δ) tend to gradually decrease. In particular, the = 0.4 alloy with remarkable magnetocaloric properties is obtained by tuning Co/Ni, which shows a giant entropy change of 48.5 J∙kgK at 309 K for 5 T and an adiabatic temperature change (Δ) of 8.6 K at 306.5 K. Moreover, the = 0.55 HEA shows great hardness and compressive strength with values of 552 HV2 and 267 MPa, respectively, indicating that the mechanical properties undergo an effective enhancement. The large Δ and Δ may enable the MnNiSi-based HEAs to become a potential commercialized magnetocaloric material.
为了改善基于MnNiSi的合金的磁热性能，构建了一种新型的高熵磁热合金。在这项工作中，发现MnNiSiFeCoGe（ = 0.4、0.45和0.5）呈现从高温NiIn型相到低温TiNiSi型相的磁结构一级相变，从而使合金能够实现巨大的磁热效应。我们研究了为什么随着Co替代 / (/) 逐渐增加，而相变温度 () 和等温磁熵变 (Δ) 却趋于逐渐降低。特别是，通过调整Co/Ni获得了具有显著磁热性能的 = 0.4合金，其在309 K下5 T时显示出48.5 J∙kgK的巨大熵变，在306.5 K时绝热温度变化 (Δ) 为8.6 K。此外， = 0.55的高熵合金显示出极大的硬度和抗压强度，分别为552 HV2和267 MPa，表明其力学性能得到了有效增强。大的Δ和Δ可能使基于MnNiSi的高熵合金成为一种潜在的商业化磁热材料。
