基于第一原理计算研究成分对Ni-Mn-In合金(中间)马氏体相变的影响规律及机理

First-principles calculations will be adopted in this research, to systematically investigate the influence of alloying composition on the phase stability of the austenitic parent phase and four martensitic phases (5M, 6M, 7M and NM) in the Ni-Mn-In alloys; to reveal the variation of the Curie temperature and (inter) martensitic transformation temperatures with the composition adjustment, and to clarify the physical nature of the effect of chemical compositions on the martensitic transformation sequence from the point of view of the formation energy. Furthermore, the variation of the magnetic properties for Ni-Mn-In alloys with the change of compositions will be discussed in detail, and the relevant mechanism will be elucidated from the point of view of the electronic density of states. According to the calculation results, optimized composition range can be predicted with the following presented performance: slightly higher martensitic transformation temperature than room temperature, wide temperature range stable modulated martensite and the best magnetic properties. The calculation results will be validated by experiments. Finally, the constitutive equation of the composition- structure- properties will be established.. The completion of this project will not only fill the gap in the theoretical study on the (inter)martensitic phase transformation of Ni-Mn-In alloys, including modulated martensite, but also will provide theoretical basis for the composition design and performance optimization. Furthermore, it will enrich the Ni-Mn-In alloys solid phase transformation theory , thus to lay a solid theoretical foundation for the performance improvement and practical application of new ferromagnetic shape memory alloys.

申请人拟采用第一原理计算的方法，系统地研究成分对Ni-Mn-In合金奥氏体和四种马氏体（5M、6M、7M和NM）相稳定性的影响；揭示居里温度和（中间）马氏体相变温度随合金成分的变化规律及作用机理，并从形成能的角度阐明化学成分对Ni-Mn-In合金马氏体转变序列影响的物理本质；揭示磁性能随合金成分变化的规律，并从电子态密度的角度阐明磁性能变化的机理。根据计算结果确定马氏体相变温度略高于室温、调制马氏体相稳定存在温度范围宽且具有优异磁性能所对应的合金成分范围，并进行实验验证，建立成分—结构—性能关系的本构方程。. 该项目的完成不仅可以填补包含调制马氏体在内的Ni-Mn-In合金（中间）马氏体相变规律和机理研究的空白，还可以为该合金的成分设计和性能优化提供理论依据。此外，还可丰富Ni-Mn-In合金固态相变理论，为新型磁控形状记忆合金的性能改进和应用奠定坚实的理论基础。

Ni-Mn-In系合金兼具大输出应变、大输出应力和高的响应频率，并伴随巨磁热效应和巨磁阻效应。这些优异的综合性能在磁驱动和磁制冷等方面的应用非常引人关注。申请人采用第一原理计算的方法，系统地研究成分对Ni-Mn-In合金奥氏体和不同马氏体相稳定性的影响；揭示居里温度和（中间）马氏体相变温度随合金成分的变化规律及作用机理，并从形成能的角度阐明化学成分对Ni-Mn-In合金马氏体转变序列影响的物理本质；揭示磁性能随合金成分变化的规律，并从电子态密度的角度阐明磁性能变化的机理。.基于第一性原理计算和实验验证发现Ni50Mn35In15合金中7M调制马氏体是最稳定的基态相。5M和NM马氏体呈现FIM态，而A和7M相呈现FM态。Ni50Mn35In15合金随着温度的降低经历了磁结构耦合相变，即铁磁态奥氏体→亚铁磁态5M马氏体→铁磁态7M马氏体。根据态密度和差分电荷密度结果分析可知，Ni原子不仅与MnMn成键，也与MnIn成键。与NM马氏体相比，7M马氏体中的Ni-Mn间的成键强度更强。Jahn-Teller效应和Ni-Mn间的成键能力都有助于7M马氏体成为Ni50Mn35In15合金中最稳定的马氏体相。.该项目的完成不仅填补了包含调制马氏体在内的Ni-Mn-In合金（中间）马氏体相变规律和机理研究的空白，还为该合金的成分设计和性能优化提供理论依据。此外，还丰富了Ni-Mn-In合金固态相变理论，为新型磁控形状记忆合金的性能改进和应用奠定坚实的理论基础。