Stability of the omega structure of transition elements

Article

关键词: AUGMENTED-WAVE METHOD;    CRYSTAL-STRUCTURES;    PHASE;    ALLOYS;    ZIRCONIUM;    TITANIUM;    METALS;    PRECIPITATION;    TRANSFORMATION;    PRESSURES;   

DOI  :  10.1103/PhysRevB.93.094108

来源: SCIE

【 摘 要 】

Properties of the omega structure are investigated for 27 transition elements from the viewpoints of thermodynamical and dynamical stability based on first-principles calculations. The thermodynamical stability of the omega structure is compared with those of the body-centered-cubic, face-centered-cubic, and hexagonal-close-packed structures. Similar to the case of those popular crystal structures, the occupation number for d orbitals is found to roughly determine relative energy and volume of the nonmagnetic omega structure. For the group 4 elements (Ti, Zr, and Hf), the omega structure is almost the lowest in energy among the investigated crystal structures and is also dynamically stable. The omega structure of the group 7 elements (Mn, Tc, and Re) is also dynamically stable. The omega Fe is found to exhibit a magnetic state with antiparallel magnetic moments. This magnetic state is the most favorable among the investigated magnetic states. The omega Fe in this magnetic state is also dynamically stable. Energies of binary alloys composed of the elements in the group 4 and those in the groups 5 and 6 are estimated by linear interpolation, and most of the alloys show concentration ranges where the omega structure is the lowest in energy among the investigated crystal structures.

【 授权许可】

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