Hierarchical densification and negative thermal expansion in Ce-based metallic glass under high pressure

Qiang Luo, Gaston Garbarino, Baoan Sun, Dawei Fan, Yue Zhang, Zhi Wang, Yajuan Sun, Jin Jiao, Xiaodong Li, Pengshan Li, Norbert Mattern, Jürgen Eckert, Jun Shen

    Research output: Contribution to journalArticlepeer-review

    29 Citations (Scopus)

    Abstract

    The polyamorphsim in amorphous materials is one of the most fascinating topics in condensed matter physics. In amorphous metals, the nature of polyamorphic transformation is poorly understood. Here we investigate the structural evolution of a Ce-based metallic glass (MG) with pressure at room temperature (RT) and near the glass transition temperature by synchrotron X-ray diffraction, uncovering novel behaviours. The MG shows hierarchical densification processes at both temperatures, arising from the hierarchy of interatomic interactions. In contrast with a continuous and smooth process for the low- to medium-density amorphous state transformation at RT, a relatively abrupt and discontinuous transformation around 5.5â €‰GPa is observed at 390â €‰K, suggesting a possible weak first-order nature. Furthermore, both positive and abnormal-negative thermal expansion behaviours on medium-range order are observed in different pressure windows, which could be related to the low-energy vibrational motions and relaxation of the weakly linked solute-centred clusters.

    Original languageEnglish
    Article number5703
    JournalNature communications
    Volume6
    DOIs
    Publication statusPublished - 2015 Feb

    ASJC Scopus subject areas

    • Chemistry(all)
    • Biochemistry, Genetics and Molecular Biology(all)
    • Physics and Astronomy(all)

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