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Ab initio generation of binary alloy foams: the case of amorphous Cu64Zr36
Jonathan Galvan-Colin 1 , Ariel Alberto Valladares * 1 , Renela Maria Valladares 2 , Alexander Valladares 2
1  Instituo de Investigaciones en Materiales, Universidad Nacional Autónoma de México
2  Facultad de Ciencias, Universidad Nacional Autónoma de México

Published: 26 April 2016 by MDPI in 2nd International Electronic Conference on Materials session Porous Materials

We report ab initio-based approaches to generate amorphous nanoporous Cu64Zr36 bulk metallic glass. Starting with two different initial configurations: an unstable crystalline sample (cCu64Zr36) and an amorphous sample (aCu64Zr36), the transferable expanding lattice method–previously used with semiconducting and pure metal systems– was applied in order to increase the volume of the cells (and atomic distances proportionally) so that the density was halved, thus obtaining 50% porosity. The initial samples were subjected to either constant room temperature ab initio molecular dynamics or geometry optimization only, which resulted in well-defined pores growing along specific spatial directions. Herewith we report partial and total pair distribution functions, as well as nearest neighbor distances and coordination numbers which let us discern discrepancies in backbone and pore topology. Also we report the bond-angle distribution which let us track the presence of icosahedral-like short-range order which is often related to the glass forming ability in amorphous alloys. The so-called depletion of the pair distribution function at mid range order reported in the literature, along with an estimation of pore sizes are also reported.