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Title: Novel shear mechanism in nanolayered composites

Abstract

Recent studies have shown that two-phase nanocomposite materials with semicoherent interfaces exhibit enhanced strength, deformability, and radiation damage resistance. The remarkable behavior exhibited by these materials has been attributed to the atomistic structure of the bi-metal interface that results in interfaces with low shear strength and hence, strong barriers for slip transmission due to dislocation core spreading along the weak interfaces. In this work, the low interfacial shear strength of Cu/Nb nanoscale multilayers dictates a new mechanism for shear banding and strain softening during micropillar compression. Previous work investigating shear band formation in nanocrystalline materials has shown a connection between insufficient strain hardening and the onset of shear banding in Fe and Fe-10% Cu, but has also shown that hardening does not necessarily offset shear banding in Pd nanomaterials. Therefore, the mechanisms behind shear localization in nanocrystalline materials are not completely understood. Our findings, supported by molecular dynamics simulations, provide insight on the design of nanocomposites with tailored interface structures and geometry to obtain a combination of high strength and deformability. High strength is derived from the ability of the interfaces to trap dislocations through relative ease of interfacial shear, while deformability can be maximized by controlling the effects ofmore » loading geometry on shear band formation.« less

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
979650
Report Number(s):
LA-UR-09-07821; LA-UR-09-7821
TRN: US201011%%348
DOE Contract Number:  
AC52-06NA25396
Resource Type:
Journal Article
Journal Name:
Nature Materials
Additional Journal Information:
Journal Name: Nature Materials
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPRESSION; DESIGN; DISLOCATIONS; GEOMETRY; HARDENING; RADIATIONS; SHEAR; SHEAR PROPERTIES; SLIP; STRAIN HARDENING; STRAIN SOFTENING

Citation Formats

Mara, Nathan, Bhattacharyya, Dhriti, Hirth, John P, Dickerson, Patricia O, and Misra, Amit. Novel shear mechanism in nanolayered composites. United States: N. p., 2009. Web.
Mara, Nathan, Bhattacharyya, Dhriti, Hirth, John P, Dickerson, Patricia O, & Misra, Amit. Novel shear mechanism in nanolayered composites. United States.
Mara, Nathan, Bhattacharyya, Dhriti, Hirth, John P, Dickerson, Patricia O, and Misra, Amit. 2009. "Novel shear mechanism in nanolayered composites". United States. https://www.osti.gov/servlets/purl/979650.
@article{osti_979650,
title = {Novel shear mechanism in nanolayered composites},
author = {Mara, Nathan and Bhattacharyya, Dhriti and Hirth, John P and Dickerson, Patricia O and Misra, Amit},
abstractNote = {Recent studies have shown that two-phase nanocomposite materials with semicoherent interfaces exhibit enhanced strength, deformability, and radiation damage resistance. The remarkable behavior exhibited by these materials has been attributed to the atomistic structure of the bi-metal interface that results in interfaces with low shear strength and hence, strong barriers for slip transmission due to dislocation core spreading along the weak interfaces. In this work, the low interfacial shear strength of Cu/Nb nanoscale multilayers dictates a new mechanism for shear banding and strain softening during micropillar compression. Previous work investigating shear band formation in nanocrystalline materials has shown a connection between insufficient strain hardening and the onset of shear banding in Fe and Fe-10% Cu, but has also shown that hardening does not necessarily offset shear banding in Pd nanomaterials. Therefore, the mechanisms behind shear localization in nanocrystalline materials are not completely understood. Our findings, supported by molecular dynamics simulations, provide insight on the design of nanocomposites with tailored interface structures and geometry to obtain a combination of high strength and deformability. High strength is derived from the ability of the interfaces to trap dislocations through relative ease of interfacial shear, while deformability can be maximized by controlling the effects of loading geometry on shear band formation.},
doi = {},
url = {https://www.osti.gov/biblio/979650}, journal = {Nature Materials},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2009},
month = {Thu Jan 01 00:00:00 EST 2009}
}