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Quantifying the origin of metallic glass formation.

ABSTRACT: The waiting time to form a crystal in a unit volume of homogeneous undercooled liquid exhibits a pronounced minimum ?X* at a 'nose temperature' T(*) located between the glass transition temperature Tg, and the crystal melting temperature, TL. Turnbull argued that ?X* should increase rapidly with the dimensionless ratio trg=Tg/TL. Angell introduced a dimensionless 'fragility parameter', m, to characterize the fall of atomic mobility with temperature above Tg. Both trg and m are widely thought to play a significant role in determining ?X*. Here we survey and assess reported data for TL, Tg, trg, m and ?X* for a broad range of metallic glasses with widely varying ?X*. By analysing this database, we derive a simple empirical expression for ?X*(trg, m) that depends exponentially on trg and m, and two fitting parameters. A statistical analysis shows that knowledge of trg and m alone is therefore sufficient to predict ?X* within estimated experimental errors. Surprisingly, the liquid/crystal interfacial free energy does not appear in this expression for ?X*.

SUBMITTER: Johnson WL

PROVIDER: S-EPMC4735709 | biostudies-other | 2016

REPOSITORIES: biostudies-other

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Quantifying the origin of metallic glass formation.

Johnson W L WL Na J H JH Demetriou M D MD

Nature communications 20160120

The waiting time to form a crystal in a unit volume of homogeneous undercooled liquid exhibits a pronounced minimum τX* at a 'nose temperature' T(*) located between the glass transition temperature Tg, and the crystal melting temperature, TL. Turnbull argued that τX* should increase rapidly with the dimensionless ratio trg=Tg/TL. Angell introduced a dimensionless 'fragility parameter', m, to characterize the fall of atomic mobility with temperature above Tg. Both trg and m are widely thought to ...[more]

PMID: 26786966

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