2000 Fiscal Year Final Research Report Summary
Interactions between chemical ordering and magnetic transitions in ferromagnetic alloys.
| Project/Area Number |
11450233
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical properties of metals
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
KAINUMA Ryosuke Graduate School of Engineering, TOHOKU UNIVERSITY, Associate Professor, 大学院・工学研究科, 助教授 (20202004)
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| Co-Investigator(Kenkyū-buntansha) |
OHNUMA Ikuo Graduate School of Engineering, TOHOKU UNIVERSITY, Research Associate, 大学院・工学研究科, 助手 (20250714)
ISHIDA Kiyohito NICHe, TOHOKU UNIVERSITY, Professor, 未来科学技術共同研究センター, 教授 (20151368)
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| Project Period (FY) |
1999 – 2000
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| Keywords | PHASE SEPARATION / ORDER-DISORDER TRANSITIONS / MAGNETIC TRANSITION / Fe-Al SYSTEM / Fe-Ga SYSTEM / Co-Al BASE SYSTEMS / THERMODYNAMICS / PHASE DIAGRAMS |
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| Research Abstract |
It is known that magnetic transition influences order-disorder transitions in the Fe-base alloys which show both the chemical ordering and magnetic transition. However, there are very few papers quantitatively discussing the interactions between those transitions. In the present project, the order-disorder and magnetic transition temperatures in some Fe-base and Co-base alloys has been examined and the interaction between them was evaluated by thermodynamic calculation using the CALPHAD-type and BWG analysis.
In order to investigate this topic, the Fe-X (X : Al, Rh, Ga and Si) systems and the Co-Al-X (X : Ti, Ni) systems had been selected. The obtained results are as follows :
(1) The magnetic and chemical ordering transition temperatures in the Fe-X (X : Al, Rh, Ga, Si) binary alloys were determined by VSM, differential scanning calorimetry (DSC) and electric resistance (ER) measurements. In the case of some alloys showing the 1st order transitions, the phase equilibrium between the ordered and disordered phases were examined by X-ray microanalysis (XMA) and transmission electron microscopy (TEM). It was clarified by these examinations that the interactions between the magnetic and chemical orderings exist there in the Fe-Al and Fe-Ga systems.
(2) The magnetic and chemical ordering transition temperatures in the Co-Al-X (X : Ti, Ni) ternary alloys were also determined by VSM and DSC measurements. The phase equilibrium between the B2 and D03 phases were examined by TEM observation.
(3) On the basis of those experimental results, the phase equilibria in the Fe-Rh and Fe-Al binary systems were analyzed using the CALPHAD-type thermodynamic calculation. In conclusions, it was proposed that since the magnetic properties are strongly affected by the degree of order in the ordered phase, and the new thermodynamic model which takes into account the interaction between the magnetic and chemical orderings should be used for precisely describing the phase stability of phases.
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