|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Bulk Metallic Glasses XIV
||Medium-range Structure and Glass-forming Ability of Metallic Glasses
||Jason J Maldonis, Pei Zhang, Paul Voyles
|On-Site Speaker (Planned)
We have used fluctuation microscopy and hybrid reverse Monte Carlo optimization to investigate the relationship between medium-range order (MRO) and glass forming ability (GFA) in metallic glasses. In Zr-Cu-Al alloys, we find a mixture of two types of MRO: crystal-like structure with approximate 6-fold rotational symmetry and icosahedral-like structure with approximate 5-fold symmetry. On annealing, Zr<SUB>50</SUB>Cu<SUB>45</SUB>Al<SUB>5</SUB>, an alloy with high GFA, becomes more icosahedral-like and less crystal-like. Zr<SUB>50</SUB>Cu<SUB>35</SUB>Al<SUB>15</SUB>, an alloy with lower GFA, becomes more crystal-like and less icosahedral-like. The difference in the stability of the two structures suggests that high GFA requires destabilizing crystal-like structures, in addition to stabilizing non-crystal-like structures. Pd<SUB>82</SUB>Si<SUB>18</SUB> has a similar mix of crystal-like and non-crystal-like MRO, but unlike Zr-Cu-Al, the two MRO types do not have different short-range order, as characterized by their Voronoi polyhedron indices. Attempts to characterize the short-range structure using rotational alignment of nearest-neighbor clusters and machine learning will be discussed.
||Planned: Supplemental Proceedings volume