Startsida
Hjälp
Sök i LIBRIS databas

     

 

Sökning: onr:0bjpqnwrx4k0hvrp > Theoretical descrip...

  • Skripnyak, Natalia,1991- (författare)

Theoretical description of Ti and Ti alloys from first principles / Natalia Skripnyak.

  • E-bokAvhandlingEngelska2020

Förlag, utgivningsår, omfång ...

  • Publicerad:Linköping :Publicerad:Department of Physics, Chemistry and Biology, Linköping University ,Publicerad:2020
  • 1 onlineresurs (ix, 84 sidor)illustrationer
  • texttxtrdacontent
  • computercrdamedia
  • online resourcecrrdacarrier

Nummerbeteckningar

  • LIBRIS-ID:0bjpqnwrx4k0hvrp
  • Ogiltigt nummer / annan version:9789179298715 (print)
  • http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-165270uri
  • urn:nbn:se:liu:diva-165270urn
  • 10.3384/diss.diva-165270doi

Kompletterande språkuppgifter

  • Språk:engelska

Ingår i deldatabas

Klassifikation

Serie

  • Linköping Studies in Science and Technology. Dissertations,0345-7524 ;2064

Anmärkningar

  • Härtill 5 uppsatser
  • Teknologie doktorsexamen
  • Ph.D. (engineering)
  • Diss. (sammanfattning) Linköping : Linköpings universitet, 2020
  • gratis
  • Modern world is known for many advanced technologies and solutions to complex problems. Technical progress runs at high speed. In order to most effectively use materials, given to us by Nature, it is important to know their properties. To do laboratory experiments is often too expensive and time consuming. Therefore, it is very important to possess the knowledge and capabilities of studying materials properties without actual experiments. I use different methods based on the laws of Quantum mechanics to conduct my investigations. In this work I studied from first principles properties of titanium and titanium alloys that are of potential interest for various applications. Titanium was chosen because of its unique properties, which are both useful and reveal interesting physics. First, I investigated elastic properties using density functional theory (DFT) in different implementations, such as the projector augmented wave (PAW) and the exact muffin-tin orbitals (EMTO) methods. The single crystal’s elastic constants C αβ of pure Ti, Ti-V, and Ti-Ni-Al alloys were obtained by calculating the total energy as a function of appropriate strains or stress-strain relations. Disordered substitutional alloys were modeled using a special quasi-random structure (SQS) technique combined with PAW as well as the coherent potential approximation (CPA) combined with EMTO. The concentration dependence of C αβ and also the family of material characteristics, such as Young’s modulus E, bulk modulus B, shear modulus G, Cauchy pressure P c , Pugh’s coefficient k, and Poisson’s coefficient ν for the TiV system were estimated and discussed. The elastic properties of alloys in the Ni-Al- Ti system were also calculated and analyzed, as well as the temperaturedependent elastic constants of pure Ti. The influence of the amount of V on the mechanical phases stability of body-centered cubic (bcc) Ti-V alloys was studied. It was found that Ti-rich Ti-V alloys are mechanically unstable in the bcc phase, but at higher concentration of V in the system the mechanical stability is increased. It was found that the Ni-Al-Ti system is mechanically stable in accordance with the requirements of mechanical stability for a cubic crystal. The first-principles calculations yielded solution enthalpies for B2 and bcc solid solution alloys. The enthalpies of bcc Ti-V alloys were calculated from first principles at 0 and 1300 K as a function of concentration using static and molecular dynamics simulations. The enthalpy curves for the B2 Ti-V alloys were described as a function of the V concentration by using the calculated solution enthalpies. The enthalpies of the β-phase Ti-V alloys decrease with increasing concentration of vanadium in the range from 0 to 1. Next, selfdiffusion in pure Ti was studied at high temperature using classical and ab initio molecular dynamics. We reveled a physical mechanism entailing a rapid collective movement of numerous (from two to dozens) neighboring titanium atoms along tangled closed-loop paths in defectfree crystal regions. Further, we addressed the effect of atomic relaxations on the formation enthalpy and the size of the tetra and octa voids in the body-centered cubic (bcc) high entropy alloys (HEA), where one of the principal elements is Ti. These are the alloys with 5 different components in equal proportions, which recently become the objects of extensive research due to their interesting properties, such as, for example, combined toughness and plasticity as well as corrosion resistance. We found that the relaxations are crucial and can change the energetically preferable distribution of elements in the periodic bcc lattice from segregated to random-alloy-like. The tetra and octa voids in HEAs can accommodate interstitial impurities that can be of interest to improve the alloy properties. We found that the distribution of void volumes due to atomic relaxations can be described by a set of Gaussians, whose number depends on the type of the void and the atomic distribution (random vs segregated). It could also be important that the largest volumes of the voids due to atomic relaxations are increased by nearly 25%.

Ämnesord och genrebeteckningar

Biuppslag (personer, institutioner, konferenser, titlar ...)

  • Abrikosov, Igor A.,1965- (preses)
  • Yakimenko, Irina I,1960- (preses)
  • Simak, Sergei I,1967- (preses)
  • Liu, Zi-Kui (opponent)
  • Linköpings universitet.Institutionen för fysik, kemi och biologi (utgivare)
  • Linköpings universitetTekniska fakulteten (utgivare)

Sammanhörande titlar

  • Del av/supplement till:channel record
  • Annan version:Skripnyak, NataliaTheoretical description of Ti and Ti alloys from first principles9789179298715

Seriebiuppslag

  • Linköping Studies in Science and Technology. Dissertations,0345-7524 ;2064

Internetlänk

Länkade data-URI:er (test)

  • https://libris.kb.se/kw7xv39phpmzv6mh#it (Skripnyak, Natalia, 1991- aut)
  • https://id.kb.se/term/sao/Titan (Titan sao)
  • https://id.kb.se/term/sao/Legeringar (Legeringar sao)
  • https://id.kb.se/term/sao/Materiall%C3%A4ra (Materiallära sao)
  • https://libris.kb.se/wt7bfdzf3rr67sh#it (Liu, Zi-Kui opn)
Inställningar Hjälp

Titeln finns på 2 bibliotek. 

Bibliotek i östra Sverige (1)

Ange som favorit

Övriga bibliotek (1)

Ange som favorit
Om LIBRIS
Sekretess
Blogg
Hjälp
Fel i posten?
Kontakt
Teknik och format
Sök utifrån
Sökrutor
Plug-ins
Bookmarklet
Anpassa
Textstorlek
Kontrast
Vyer
LIBRIS söktjänster
SwePub
Sondera
Uppsök

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

Copyright © LIBRIS - Nationella bibliotekssystem

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy