Tuning correlative heterogeneity and related properties in Ni-Nb-TM (TM=Zr, Y, Gd) metallic glasses

Authors
Eun Soo ParkH. S. AhnS. Y. KimT. G. ParkH. S. OhHye Jung ChangW.H. Ryu
Issue Date
2022-02
Publisher
The Minerals, Metals and Materials Society (TMS)
Citation
TMS 2022 Annual Meeting & Exhibition
Abstract
Herein, we systematically investigated how to tailor correlative heterogeneity and related properties in Ni-Nb-(Zr, Y, Gd) metallic glasses (MGs). The Ni60Nb40-xZrx MGs (x=0-20 at.%) with Nb-Zr atomic pair (??H?mix=+4 kJ/mol) exhibited correlative atomic scale chemical and topological heterogeneities upon Zr addition, which can be evaluated by EXAFS analysis. Interestingly, a statistical analysis of strain burst sizes along with in situ bending test showed that the easier nucleation of chaotic shear bands is promoted with the aid of stress localization induced by the heterogeneities. The bulk specimens (d=1 mm) for 8 and 10 at.% of Zr with increased glass-forming ability (GFA) exhibited enhanced plasticity without the reduction of fracture strength, implying cooling rate effect on heterogeneity-induced plasticity. Contrastively, the Ni60Nb40-y(Y, Gd)y MGs with Nb-Y or Nb-Gd atomic pair (??H?mix=+30 kJ/mol) showed hierarchically correlative nanoscale phase separated microstructures, which can be carefully interpreted by construction of metastable miscibility gap. The microstructures rely on four different variables (the composition, the symmetry of a miscibility gap, the critical temperature and the GFA of each phase) and provide a weak interface resulting in extreme brittleness as well as drastically decreased GFA. We believe that the results of this study would provide an effective guideline for tuning correlative heterogeneity and related properties in MGs via manipulation of enthalpy relationship and cooling rate.
ISSN
-
URI
https://pubs.kist.re.kr/handle/201004/77253
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KIST Conference Paper > 2022
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