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Structural, electronic and vibrational properties of ordered intermetallic alloys CoZ (Z = Al, Be, Sc and Zr) from first-principles total-energy calculations      
Yazarlar
Şule Uğur
Gazi Üniversitesi, Türkiye
Doç. Dr. Ahmet İYİGÖR
Kırşehir Ahi Evran Üniversitesi, Türkiye
Zoulikha Charifi
Hakim Baaziz
Mehmet Recai Ellialtıoğlu
Özet
Self-consistent band calculations on four intermetallic compounds of the CsCl structure are presented. The calculations were performed employing the self-consistent ultrasoft pseudopotential method based on the density functional theory, within the local density approximation and the generalized gradient approximation. The calculations predicted that the equilibrium lattice constants are in excellent agreement with the experiment for CoAl and are 1% smaller than experimental values for CoBe, CoSc and CoZr, respectively. In the present study, ordered CoAl do not show any magnetic moment, whereas the other three compounds have moderate magnetic moments of about 0.2 and 0.7 Bohr magnetons ((B) ) per atom. The elastic constants are calculated using two approaches, the energy-strain method and the use of phonon dispersion curves. The values obtained from the two methods are in reasonable agreement for the studied intermetallic compounds CoZ (Z=Al, Be, Sc and Zr). The brittleness and ductility properties of CoZ (Z=Al, Be, Sc and Zr) are determined by Poisson's ratio sigma criterion and Pugh's criterion. The calculated elastic constants satisfy the mechanical stability criterion and the ductility of CoZr and CoSc is predicted by Pugh's criterion. The band structure and density of states, and phonon dispersion curves have been obtained and compared with the available experimental results as well as with existing theoretical calculations. We studied and discussed the position of Fermi level for the selected four intermetallic compounds.
Anahtar Kelimeler
density-functional theory, elastic constants, ductility, intermetallic alloys, vibrational properties
Makale Türü Özgün Makale
Makale Alt Türü SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale
Dergi Adı Philosophical Magazine
Dergi ISSN 1478-6435
Dergi Tarandığı Indeksler SCI-Expanded
Makale Dili İngilizce
Basım Tarihi 06-2013
Cilt No 93
Sayı 24
Sayfalar 3260 / 3277
Doi Numarası 10.1080/14786435.2013.806828
Makale Linki http://www.tandfonline.com/doi/abs/10.1080/14786435.2013.806828