Zhang, Guoyun and An, Qi and Goddard, William A., III (2011) Composition Dependence of Glass Forming Propensity in Al−Ni Alloys. Journal of Physical Chemistry C, 115 (5). pp. 2320-2331. ISSN 1932-7447 http://resolver.caltech.edu/CaltechAUTHORS:20110317-132727662
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Enormous progress has been made over the past decade in developing bulk amorphous alloys with high strength and other mechanical properties while possessing improved glass forming and processing abilities. Particularly important in developing new systems is identifying the compositions most likely to lead to glass formation. We illustrate here for the Al−Ni system how Molecular Dynamics (MD) using a force field derived from first-principles quantum mechanics (QM) can be used to determine the optimum compositions for glass forming ability (GFA). Using the Two-Phase Thermodynamics (2PT) method to extract entropy and free energy directly from MD, we find that the GFA is closely related to (ΔG_(lc))_(Tg), the Gibbs free energy difference between the liquid state and crystal state at the glass transition temperature T_g. We find that the glass phase is preferred at compositions where (ΔG_(lc))_(Tg) is small and where the equilibrium crystal structure is complex. For the AlNi alloys, our calculations suggest that the best glass-forming composition is 87.5% Al and 12.5% Ni. On the basis of the Honeycutt−Andersen type of local structure analysis of alloys in the liquid state, we propose an atomic scale explanation of GFA. Large GFA arises when there is a great difference in the atom bonding preference between different atom species.
|Additional Information:||© 2011 American Chemical Society. Received: August 05, 2010; Revised: November 16, 2010. Article ASAP January 10, 2011; Published In Issue February 10, 2011. We thank Qing Zhang, Shiang-Tai Lin, Hyon-Jee Lee, and Tahir Cagin for helpful discussions. This research was supported partially by NSF-MRSEC-CSEM DMR-0520565.|
|Official Citation:||Composition Dependence of Glass Forming Propensity in Al−Ni Alloys Guoyun Zhang, Qi An, William A. Goddard III The Journal of Physical Chemistry C 2011 115 (5), 2320-2331|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||17 Mar 2011 20:45|
|Last Modified:||26 Dec 2012 13:05|
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