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The structural relaxation effect on functional properties of Fe - based amorphous alloys

dc.contributor.advisorMaričić, Aleksa
dc.contributor.otherDojčilović, Jablan
dc.contributor.otherNovaković, Lazar
dc.creatorKalezić-Glišović, Aleksandra S.
dc.date.accessioned2016-01-05T12:51:18Z
dc.date.available2016-01-05T12:51:18Z
dc.date.available2020-07-03T09:49:58Z
dc.date.issued2012-11-09
dc.identifier.urihttp://eteze.bg.ac.rs/application/showtheses?thesesId=698
dc.identifier.urihttp://nardus.mpn.gov.rs/handle/123456789/3193
dc.identifier.urihttps://fedorabg.bg.ac.rs/fedora/get/o:6945/bdef:Content/download
dc.identifier.urihttp://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=44663567
dc.description.abstractIspitivan je uticaj strukturnih promena izazvanih primenom spoljašnjih parametara (toplotno dejstvo, magnetno dejstvo, mehaničko naprezanje) u toku procesa strukturne relaksacije i kristalizacije na funkcionalna svojstva tri legure na bazi gvožđa, različitog hemijskog sastava: Fe89.8Ni1.5Si5.2B3C0.5, Fe81B13Si4C2 i Fe73.5Cu1Nb3Si15.5B7. Legure su dobijene brzim hlađenjem rastopa na rotirajućem disku (melt-spinning). Uzorci su bili u obliku trake dužine 20 cm, širine 2 mm i debljine 3 μm. Strukturna stabilnost i strukturne transformacije legura ispitane su primenom difrakcije Xzraka. Pokazana je egzotermna termička stabilnost ispitivanih legura u temperaturskom intervalu od 200C - 7000C, primenom diferencijalne skanirajuće kalorimetrije (DSC). Ovaj temperaturski interval obuhvata relaksaciju deformisane strukture, gubitak feromagnetičnosti i konačno kristalizaciju, rekristalizaciju i rast kristala formiranih faza. Proces kristalizacije obuhvata formiranje različitih stabilnih i nestabilnih faza u zavisnosti od hemijskog sastava ispitivanih legura. Ispitana je kinetika procesa strukturne relaksacije ovih legura, pri različitim naprezanjima i temperaturama odgrevanja. Zatim je ispitan uticaj strukturne relaksacije na promenu gustine stanja elektrona na Fermi-evom nivou. Pokazano je da strukturne promene imaju velikog uticaja na električna i magnetna svojstva ovih legura. Utvrđeno je da relaksirana amorfna struktura legure poseduje znatno bolja električna i magnetna svojstva kako u odnosu na polaznu leguru, tako i u odnosu na iskristalisalu leguru sa stanovišta mogućnosti praktične primene. Takođe je ispitana i mogućnost primene ovih legura kao senzora sile. Uspostavljena je jasna korelacija strukturne promene – funkcionalna svojstva i dato fundamentalno tumačenje međuzavisnosti strukturna relaksacija – promena gustine stanja elektrona na Fermi-evom nivou – električna svojstva – magnetna svojstva, što je i cilj ove disertacije.sr
dc.description.abstractThe effect of structural changes was investigated, induced by the application of external parameters (thermal influence, magnetic influence, mechanical strain) within the structural relaxation process and crystallization, over the functional properties of three Fe-based alloys of various chemical content: Fe89.8Ni1.5Si5.2B3C0.5, Fe81B13Si4C2 and Fe73.5Cu1Nb3Si15.5B7. The alloys were obtained by rapidly quenching of the melt on a rotating disk (melt-spinning technique). The samples were ribbon-shaped, 20 cm long, 2 mm wide and 3 μm thick. The structural stability and structural transformations of the alloys were investigated by X - ray diffraction. Exothermal stability of the investigated alloys in the temperature range from 200C to 7000C was determined, by the differential scanning calorimetry method (DSC). This temperature range presumes relaxation of deformed structure, the loss of ferromagnetic properties and finally crystallization, recrystallization and growth of the crystallites of formed phases. The crystallization process includes the formation of various stable and unstable phases depending on the chemical content of the investigated alloys. The kinetics of the structural relaxation process of these alloys was investigated at different strain intensities and annealing temperatures. Furthermore, the structural relaxation effect on the electron state density change at Fermi level was investigated. It has been shown that the structural changes have significant effect on electrical and magnetic properties of these alloys. It has been determined that the relaxed amorphous structure of the alloy possesses far better electrical and magnetic properties as compared to both the as-cast alloy and the crystallized alloy, from their technological applicability aspect. In addition, the possibility of application of these alloys as power sensors has also been investigated. A clear correlation of structural changes – functional properties has been determined, as well as the given fundamental interpretation of the interdependence structural relaxation – electron state density change at Fermi level – electrical properties – magnetic properties, which is the aim of this dissertation.en
dc.formatapplication/pdf
dc.languagesr
dc.publisherУниверзитет у Београду, Физички факултетsr
dc.relationinfo:eu-repo/grantAgreement/MESTD/Basic Research (BR or ON)/172057/RS//
dc.rightsopenAccessen
dc.sourceУниверзитет у Београдуsr
dc.subjectamorfne metalne leguresr
dc.subjectamorphous metallic alloysen
dc.subjectmelt-spinning techniqueen
dc.subjectdifferential scanning calorimetry methoden
dc.subjectX - ray diffractionen
dc.subjectstructural relaxationen
dc.subjectthermal influenceen
dc.subjectmechanical strainen
dc.subjectelectrical propertiesen
dc.subjectelectron state density change at Fermi levelen
dc.subjectmagnetic propertiesen
dc.subjectmelt-spinningsr
dc.subjectDSCsr
dc.subjectdifrakcija X-zračenjasr
dc.subjectstrukturna relaksacijasr
dc.subjecttoplotno dejstvosr
dc.subjectmehaničko naprezanjesr
dc.subjectelektrična svojstvasr
dc.subjectgustina stanja elektrona na Fermi-evom nivousr
dc.subjectmagnetna svojstvasr
dc.titleUticaj strukturne relaksacije na funkcionalna svojstva amorfnih legura na bazi gvožđasr
dc.titleThe structural relaxation effect on functional properties of Fe - based amorphous alloysen
dc.typedoctoralThesis
dc.rights.licenseBY-NC-SA
dcterms.abstractМаричић, Aлекса; Новаковић, Лазар; Дојчиловић, Јаблан; Калезић-Глишовић, Aлександра С.; Утицај структурне релаксације на функционална својства аморфних легура на бази гвожђа; Утицај структурне релаксације на функционална својства аморфних легура на бази гвожђа;
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/24859/Disertacija.pdf


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