Theoretical and experimental studies of devitrification pathways in the Zr2Cu1-xPdx metallic glass system

TitleTheoretical and experimental studies of devitrification pathways in the Zr2Cu1-xPdx metallic glass system
Publication TypeJournal Article
Year of Publication2007
AuthorsMorris JR, Xu M, Ye YY, Sordelet DJ, Kramer MJ
Journal TitleActa Materialia
Volume55
Pages5901-5909
Date PublishedOct
Type of ArticleArticle
ISBN Number1359-6454
Accession NumberISI:000250355700022
Keywordsab initio electron theory, amorphous-alloys, BINARY ZR-PD, devitrification, electronic-structure, metallic glasses, metastable phases, NANOQUASICRYSTALLINE PHASE, PRIMARY CR, QUASI-CRYSTALS, Synchrotron radiation, total-energy calculations, wave basis-set
Abstract

Using a model amorphous alloy series, Zr2Cu1-xPdx (x = 0, 0.25, 0.5, 0.75 and 1), we demonstrate that ab initio calculations can predict likely metastable phase formation during devitrification by comparing these with time-resolved X-ray scattering studies. All compositions share the same equilibrium C11(b) phase, yet they follow different devitrification pathways. Only x = 0.5 leads to a metastable C16 phase formation. This corresponds precisely to calculations showing the C16 phase is closest in energy to the stable C11(b) phase. The competition is shown to be dominated by electronic structure rather than size effects, with the favored composition for the C16 phase forming a pseudo-gap at the Fermi energy. All Pd-containing compounds devitrify first into a quasicrystal line phase. Zr2Cu1-xPdx compounds based on the NiTi2 O-h(5) structure are higher in energy relative to the C16 and C11(b) structures for all compositions, and the calculations show no increase in stability with Pd concentration. Published by Elsevier Ltd on behalf of Acta Materialia Inc.

DOI10.1016/j.actamat.2007.07.021
Alternate JournalActa Mater.