A_(2)BTi型磁性功能合金相稳定性、磁性与力学性能的第一性原理计算和实验研究  

Phase Stability,Magnetism,and Mechanical Properties of A_(2)BTi:First-Principles Calculations and Experimental Studies

作　　者：杨谨菡 闫海乐 刘昊轩 赵莹 杨一俏[2] 赵骧 左良 YANG Jinhan;YAN Haile;LIU Haoxuan;ZHAO Ying;YANG Yiqiao;ZHAO Xiang;ZUO Liang(Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education),School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;Analytical and Testing Center,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学材料科学与工程学院、材料各向异性与织构教育部重点实验室,沈阳110819 [2]东北大学分析测试中心,沈阳110819

出　　处：《金属学报》2024年第12期1701-1709,共9页Acta Metallurgica Sinica

基　　金：中央高校基本科研业务费项目Nos.N2202015和N2230002。

摘　　要：探究新型磁性Heusler合金对于开发新一代智能传感材料具有重要的意义。本工作采用第一性原理计算对8种新型A_(2)BTi型磁性功能合金,包括3种钴基合金(Co_(2)MnTi、Co_(2)FeTi和Co_(2)NiTi)、3种铁基合金(Fe_(2)MnTi、Fe_(2)CoTi和Fe_(2)NiTi)以及2种镍基合金(Ni_(2)FeTi、Ni_(2)CoTi),在四方晶格畸变过程中的相稳定性演化进行了理论计算,并对其L2_(1)相稳定性演变规律及背后机制进行了探讨。研究发现,价电子浓度和磁性是决定A_(2)BTi型合金L2_(1)相结构稳定性的关键参数。针对理论计算筛选出的L2_(1)相为非最稳定结构的Co_(2)NiTi、Fe_(2)NiTi和Ni_(2)CoTi,分别制备了合金样品并对其晶体结构、相变行为、磁性能、电阻和力学性能进行了实验研究。结果表明,室温下Co_(2)NiTi由有序面心立方L12结构基体相和六方Co_(3)Ti型第二相构成,Fe_(2)NiTi由六方Fe_(2)Ti型基体相和四方FeNi型第二相构成,Ni_(2)CoTi为单一的Ni_(3)Ti型六方结构。Co_(2)NiTi、Fe_(2)NiTi和Ni_(2)CoTi均不存在一阶结构相变,这可能与其L2_(1)结构低的晶格稳定性致使其难以被形成有关。Fe_(2)NiTi和Ni_(2)CoTi具有较强的磁性且存在二阶Curie磁性转变。Fe_(2)NiTi具有高的压缩强度(1280 MPa)、中等压缩应变(5%)及较大电阻(120μΩ·cm),而Co_(2)NiTi和Ni_(2)CoTi具有优异的压缩塑性和较小的电阻,这3种合金不同的功能行为可能与其价电子浓度差异带来的化学键中金属键和共价键组分比例不同有关。Exploring novel magnetic Heusler alloys is of great significance for the development of a new generation of smart sensing materials.The A2BC type magnetic alloy,which comprises transition magnetic metal elements A and B and III-V main group element C(p-block element),has gained signifi-cant attention due to its various physical and chemical properties,including semimetallic magnetism,ferromagnetic shape memory effect,multicaloric effect,and superconductive effect.In this study,eight new A_(2)BTi type magnetic functional alloys,including three Co-based alloys(Co_(2)MnTi,Co_(2)FeTi,and Co_(2)NiTi),three Fe-based alloys(Fe_(2)MnTi,Fe_(2)CoTi,and Fe_(2)NiTi),and two Ni-based alloys(Ni_(2)FeTi and Ni_(2)CoTi),were investigated for their phase stability against tetragonal distortion using first-principles calculation.The underlying mechanism for the stability of the L2_(1) phase was discussed.The results show that valence electron concentration and magnetism are the key parameters in determining the structural stability of L2_(1) phase in A_(2)BTi type alloys.Co_(2)NiTi,Fe_(2)NiTi,and Ni_(2)CoTi alloy samples,whose L2_(1) structure is an unstable phase,were prepared,and their crystal structure,phase transformation,magnetic properties,electrical resistance,and mechanical properties were investigated experimentally.The results show that at 298 K,Co_(2)NiTi is composed of an ordered face-centered cubic L12 structured matrix phase and a hexagonal Co_(3)Ti-type second phase,Fe_(2)NiTi is composed of a hexagonal Fe_(2)Ti-type matrix phase and a tetragonal FeNi-type second phase,and Ni_(2)CoTi has a single hexagonal Ni_(3)Ti-type structure.The fact that no compound undergoes a first-order structural phase transition may be due to the weak stabilities of their L2_(1) phases.Fe_(2)NiTi and Ni_(2)CoTi have strong magnetic properties and undergo a second-order Curie magnetic transition during cooling.Fe_(2)NiTi has high compressive strength(1280 MPa),moderate compressive strain(5%),and large resistance(120μΩ·cm),while Co_(2)Ni

关 键 词：磁性功能材料 磁性形状记忆合金 HEUSLER合金 马氏体相变 第一性原理计算 

分 类 号：TG139.6[一般工业技术—材料科学与工程]