Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 51: Nanomaterials - Nanocrystalline & Porous Materials I

MM 51.1: Talk

Thursday, March 14, 2013, 10:15–10:30, H25

Molecular dynamics simulations of free volume redistribution in metallic nanoglasses — •Omar Adjaoud and Karsten Albe — Technische Universität Darmstadt, Fachbereich Material- und Geowissenschaften, Fachgebiet Materialmodellierung, Petersenstr. 32, D-64287 Darmstadt, Germany

Nanoglasses are formed with glassy regions separated by interfacial areas which are called glass-glass interfaces. These interfaces influence many properties of nanoglasses such as mechanical properties. The structure arrangement at the interfaces produces excess free volume. The nanoglasses properties depend on the structure and density of their interfaces. Therefore, a detailed study of the structure and density of glass-glass interfaces is required to understand nanoglasses properties.

In the present study, we have performed molecular dynamics (MD) simulations to model excess free volume and structure of glass-glass interfaces in a metallic glass (MG) Cu64Zr36 and a MG Pd80Si20 which is a representative of metal-metalloid systems. The interactions between the atoms are described by embedded atom model. The free volume was created by randomly diluting a sphere of 1 nm radius in the simulation box of 5.8x5.8x5.8 nm dimensions for different densities with respect to the bulk glass density. For each density the system was monitored in MD runs by following the density redistribution throughout the sample with time. As a second set of simulations, a cluster of four glassy spheres of 5 nm diameter were created to form a free volume between them. The evaluation of the free volume was followed by MD simulations. The results are compared to experimental observations.