Hidden phase transitions in metallic glasses and their applications

  • [2018-01-29]

    Speaker: Prof. SI Lan
    Nanjing University of Science and Technology
    Time: 2018-01-29 10:30
    Place: ROOM 9004, Hefei National Laboratory Building

    Detail:

    Abstract:
      Metallic glasses (MGs) constitute a new class of metastable metallic materials with unique properties, including high strength, high elastic limit, high wear and corrosion resistance, and excellent soft magnetic behavior, and promising high catalysis efficiency, for structural and functional applications. Phase transformations, including devitrification, liquid-liquid phase transition, liquid phase decompositions, in MGs, are suppressed upon quenching the molten liquids to room temperature. The hidden phase transitions thus open a window for studying the origin of the glass formation and shed lights on potential applications. In this talk, I will first briefly introduce the history of MGs and a half-century mystery about an anomalous exothermic phenomenon (AEP) which relates to a hidden liquid phase transition during heating the prototypical MGs with an AEP above glass transition temperature. The results, revealed by unitizing a suite of in-situ techniques including X-ray and neutron scattering as well as double Cs-corrected transmission electron microscopy, will be presented to solve the half-century problem. At the second part of the talk, I will present how to develop a prototypical free-standing porous metallic glasses based on the hidden phase transitions for electrocatalyst applications.

    Selected Publications
      1. Lan S, Ren Y, Wei X Y, Wang B, Gilbert E P, Shibayama T, Watanabe S, Ohnuma M, and Wang X -L, Hidden amorphous phase and reentrant supercooled liquid in Pd-Ni-P metallic glasses [J]. Nature Communications, 8, 14679 (2017): 1-8. Doi: 10.1038/NCOMMS14679
      2. Lan S, Blodgett M, Kelton K F, et al. Structural crossover in a supercooled metallic liquid and the link to a liquid-to-liquid phase transition [J]. Applied Physics Letters, 2016, 108(21): 211907.
      3. Lan S, Wei X, Zhou J, et al. In-situ study of crystallization kinetics in ternary bulk metallic glass alloys with different glass forming abilities [J]. Applied Physics Letters, 2014, 105(20): 201906.

    Organizer: Hefei National Laboratory for Physical Sciences at the Microscale
       

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