Microyielding of core-shell crystal dendrites in a bulk-metallic-glass matrix composite

E. Wen Huang, Junwei Qiao, Bartlomiej Winiarski, Wen Jay Lee, Mario Scheel, Chih Pin Chuang, Peter K. Liaw, Yu Chieh Lo, Yong Zhang, Marco Di Michiel

    Research output: Contribution to journalArticlepeer-review

    Abstract

    In-situ synchrotron x-ray experiments have been used to follow the evolution of the diffraction peaks for crystalline dendrites embedded in a bulk metallic glass matrix subjected to a compressive loading-unloading cycle. We observe irreversible diffraction-peak splitting even though the load does not go beyond half of the bulk yield strength. The chemical analysis coupled with the transmission electron microscopy mapping suggests that the observed peak splitting originates from the chemical heterogeneity between the core (major peak) and the stiffer shell (minor peak) of the dendrites. A molecular dynamics model has been developed to compare the hkl-dependent microyielding of the bulk metallic-glass matrix composite. The complementary diffraction measurements and the simulation results suggest that the interface, as Maxwell damper, between the amorphous matrix and the (211) crystalline planes relax under prolonged load that causes a delay in the reload curve which ultimately catches up with the original path.

    Original languageEnglish
    Article number4394
    JournalScientific Reports
    Volume4
    DOIs
    Publication statusPublished - 18 Mar 2014

    Keywords

    • Mechanical properties
    • Metals and alloys

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