Relating Dynamic Properties to Atomic Structure in Metallic Glasses

TitleRelating Dynamic Properties to Atomic Structure in Metallic Glasses
Publication TypeJournal Article
Year of Publication2012
AuthorsSheng HW, Ma E, Kramer MJ
Journal TitleJOM
Volume64
Pages856-881
Date Published07
Type of ArticleArticle
ISBN Number1047-4838
Accession NumberWOS:000306951000018
Keywordsamorphous-alloys, correlation length, energy landscape, open volume regions, short-range order, simple-model glass, sphere packings, supercooled liquids, vibrational-modes, vitreous silica
Abstract

Atomic packing in metallic glasses is not completely random but displays various degrees of structural ordering. While it is believed that local structures profoundly affect the properties of glasses, a fundamental understanding of the structure-property relationship has been lacking. In this article, we provide a microscopic picture to uncover the intricate interplay between structural defects and dynamic properties of metallic glasses, from the perspective of computational modeling. Computational methodologies for such realistic modeling are introduced. Exploiting the concept of quasi-equivalent cluster packing, we quantify the structural ordering of a prototype metallic glass during its formation process, with a new focus on geometric measures of subatomic "voids." Atomic sites connected with the voids are found to be crucial in terms of understanding the dynamic, including vibrational and atomic transport, properties. Normal mode analysis is performed to reveal the structural origin of the anomalous boson peak (BP) in the vibration spectrum of the glass, and its correlation with atomic packing cavities. Through transition-state search on the energy landscape of the system, such structural disorder is found to be a facilitating factor for atomic diffusion, with diffusion energy barriers and diffusion pathways significantly varying with the degree of structural relaxation/ordering. The implications of structural defects for the mechanical properties of metallic glasses are also discussed.

URL<Go to ISI>://WOS:000306951000018
DOI10.1007/s11837-012-0360-y
Alternate JournalJom