In this work,the effects of Co doping on the magnetostructural coupling transformation of Ni50-xCoxMn50-yTiy(x=0-15,y=12.5-15)Heusler alloys were systematically investigated through the first-princi-ples calculations and experimental verification.The cal-culation result indicates that the doped Co atoms prefer to occupy the Ni sublattice.The Co atoms tend to flock together in terms of the lowest energy principle.Since the formation energy of the austenite is higher than that of the martensite,the alloys will undergo martensitic transfor-mation for the Ni50-xCoxMn37.5Ti1 2.5 alloys(x=0-12.5).The magnetostructural coupling point of Ni50-xCoxMn37.5Ti12.5 alloys is predicted in the vicinity of x=11-12.Based on the computational composition Ni37.5Co12.5Mn37.5Ti12.5,the Ni36Co14Mn36Ti14 alloy with magnetostructural coupling near room temperature was experimentally developed by simultaneously increasing the Ti and Co contents.The largest magnetization change(ΔM)and magnetic entropy changes(ΔSm)obtained under magnetic field of 5 T for the martensitic transformation in the Ni36Co14Mn36Ti14 alloy are about 87.6 A·m2·kg-1 and 21 J·kg-1·K-1,respectively.The fracture strength and strain for non-textured polycrystalline Ni36Co14Mn36Ti14 alloy reach 953 MPa and 12.3％,respectively.The results show that the alloy not only possesses a large magne-tocaloric effect but also has excellent mechanical proper-ties.In addition,the 6 M modulated martensite is evidenced in the Ni-Co-Mn-Ti alloys via transmission electron microscopy technique.

Zi-Qi Guan;Jing Bai;Yu Zhang;Jiang-Long Gu;Xin-Jun Jiang;Xin-Zeng Liang;Run-Kai Huang;Yu-Dong Zhang;Claude Esling;Xiang Zhao;Liang Zuo

Key Laboratory for Anisotropy and Texture of Materials,School of Material Science and Engineering,Northeastern University,Shenyang 110819,China;School of Resources and Materials,Northeastern University at Qinhuangdao,Qinhuangdao 066004,China;State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,China;Hebei Provincial Laboratory for Dielectric and Electrolyte Functional Materials,Qinhuangdao 066004,China;Laboratoire d'étude des Microstructures et de Mécanique des Matériaux,University of Lorraine,Metz 57045,France

稀有金属（英文版）

[1]Zi-Qi Guan;Jing Bai;Yu Zhang;Jiang-Long Gu;Xin-Jun Jiang;Xin-Zeng Liang;Run-Kai Huang;Yu-Dong Zhang;Claude Esling;Xiang Zhao;Liang Zuo-.Revealing essence of magnetostructural coupling of Ni-Co-Mn-Ti alloys by first-principles calculations and experimental verification)[J].稀有金属（英文版）,2022(06):1933-1947

magnetostructural,xCoxMn50,yTiy,xCoxMn37,5Ti12,Ni37,5Co12,5Mn37,Ni36Co14Mn36Ti14,tocaloric

Revealing,essence,coupling,alloys,by,first,principles,calculations,verification,In,this,work,effects,doping,transformation,Ni50,Heusler,were,systematically,investigated,through,indicates,that,doped,atoms,prefer,occupy,sublattice,tend,flock,together,terms,lowest,energy,Since,austenite,higher,than,martensite,will,undergo,martensitic,point,predicted,vicinity,Based,computational,composition,near,room,temperature,was,experimentally,developed,simultaneously,increasing,contents,largest,magnetization,magnetic,entropy,changes,Sm,obtained,field,are,about,respectively,fracture,strength,strain,textured,polycrystalline,reach,results,show,not,only,possesses,but,also,has,excellent,mechanical,proper,ties,addition,modulated,evidenced,via,transmission,electron,microscopy,technique

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