Deformation of Heterogeneous Nanocrystalline Lamella with a Preexisting Crack

Abstract

Molecular dynamics simulations were performed on heterogeneous nanocrystalline Al lamellae composed of nanocrystalline (NC) and single-crystalline (SC) layers to study the effect of the heterogeneous microstructures on the propagation of preexisting cracks. Under tensile loading, the heterogeneous NC Al lamella exhibited higher crack growth resistance than the pure NC Al. In addition, a lower volume fraction of the NC layer provided better crack growth resistance in heterogeneous lamellae (HL) samples, which agrees well with previous experiment results. After analyzing the distribution of the atom-level virial stress and microstructure evolution during the deformation, we found that the average stress on grain boundary atoms was much lower in HL samples than that in pure NC sample. When the crack approaches the interface, the heterogeneous microstructure can reduce the stress concentration by emitting dislocations from the interface into the SC layer.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Aluminum; Crack Propagation; Cracks; Deformation; Grain Boundaries; Microstructure; Molecular Dynamics; Wrought Iron, Crack-Growth Resistance; Heterogeneous Microstructure; Micro-Structure Evolutions; Molecular Dynamics Simulations; Nanocrystalline Al; Nanocrystallines; Pre-Existing Crack; Single-Crystalline, Nanocrystals

International Standard Serial Number (ISSN)

1047-4838; 1543-1851

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 Minerals, Metals and Materials Society (TMS), All rights reserved.

Publication Date

01 Jan 2018

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