Structural changes and kinetics of shear banding in metallic glass composites

Autor(es)

Tercini, Marcela ^[1] ; de Aguiar Veiga, Roberto Gomes ^[1] ; Zuniga, Alejandro ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Abc, CECS, Santo Andre, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Alloys and Compounds; v. 819, APR 5 2020.
• Citações Web of Science: 0

Resumo

In this work we studied the mechanical behavior, structural changes and kinetics of shear banding during compression tests of Cu-Zr-based metallic glass composites using molecular dynamics simulations. Starting from a Cu45Zr45Al10 metallic glass model, two composite models were generated by adding 2% in volume of CuZr (B2 structure) nanocrystals of 4 and 17 nm in diameter, respectively. The three models were then deformed in compression using embedded-atom method (EAM) interatomic potentials. Local shear strain analyses showed that the kinetics of shear banding could be modeled as a two-stage process: 1) shear band formation due to the coalescence of shear transformation zones, and 2) shear band coarsening/thickening. The growth rate of the first stage (coalescence of shear transformation zones) varied upon the addition of CuZr nanocrystals, while the growth rate of the second stage remained unchanged. The addition of CuZr nanocrystals did not induce significant changes in the radial distribution function and distribution of Voronoi polyhedra of the glassy matrix, independently of the nanocrystal size. However, the addition of CuZr nanocrystals induced changes in the rate at which the local density of Cu-centered < 0, 0, 12, 0, 0 > icosahedra decreased with strain ({''}kinetics of icosahedra destruction{''}). These changes in local density were also modeled as a two-stage process with corresponding growth rates very similar to those obtained for the kinetics of shear banding, thus indicating a close relationship between the kinetics of icosahedra destruction and the kinetics of shear banding. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 18/23172-5 - Desenvolvimento de potenciais empíricos para a simulação computacional de materiais
• Beneficiário: Roberto Gomes de Aguiar Veiga
• Modalidade de apoio: Auxílio à Pesquisa - Regular