The first order L-G phase transition in liquid Ag and Ag-Cu alloys is driven by deviatoric strain
An undercooled liquid-phase (L-phase) can undergo a first order configurational phase transition to either a crystal phase (X-phase) or a metastable, configurationally heterogeneous, rigid glassy phase (G-phase). To investigate the underlying mechanism of the L-G transition, we employ molecular dynamics simulations to study G-phase formation in a binary Cu-Ag system. We find that G-phase formation is driven by the reduction of local distortion energy arising from deviatoric strains in the liquid phase and demonstrate its local distribution. Reduction of distortion energy contributes over 80% of the latent heat of the L-G transition, suggesting that condensation of spatially varying random elastic fields in the liquid is primarily responsible for the first order L-G transition. By applying this analysis to crystallization and G-phase formation in elementary Ag, we show that deviatoric strain energy is the dominant driving force for the L-G and L-X transition also in the case of the pure metal.
© 2020 Acta Materialia Inc. Published by Elsevier Ltd. Received 4 November 2020, Revised 17 December 2020, Accepted 21 December 2020, Available online 30 December 2020. W.L.J and S.C. are supported by NSF grant with the award number DMR 1710744. K.S. is supported by the DFG, grant Sa337/10. W.A.G. I supported by ONR (N00014-19-1-2081). The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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