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This content will become publicly available on January 10, 2019

Title: Analyzing shear band formation with high resolution X-ray diffraction

Localization of crystallographic slip into shear bands during uniaxial compression of a copper single crystal is studied using very far-field high-energy diffraction microscopy (vff-HEDM). Diffracted intensity was collected in-situ as the crystal deformed using a unique mobile detector stage that provided access to multiple diffraction peaks with high-angular resolution. From the diffraction data, single crystal orientation pole figures (SCPFs) were generated and are used to track the evolution of the distribution of lattice orientation that develops as slip localizes. To aid the identification of ‘signatures’ of shear band formation and analyze the SCPF data, a model of slip-driven lattice reorientation within shear bands is introduced. Confidence is built in conclusions drawn from the SCPF data about the character of internal slip localization through comparisons with strain fields on the sample surface measured simultaneously using digital image correlation. From the diffraction data, we find that the active slip direction and slip plane are not directly aligned with the orientation of the shear bands that formed. In fact, by extracting the underlying slip system activity from the SCPF data, we show that intersecting shear bands measured on the surface of the sample arise from slip primarily on the same underlying single slipmore » system. These new vff-HEDM results raise significant questions on the use of surface measurements for slip system activity estimation.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Cornell Univ., Ithaca, NY (United States). Cornell High Energy Synchrotron Source (CHESS)
  2. Cornell Univ., Ithaca, NY (United States). Sibley School of Mechanical and Aerospace Engineering
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
  4. Cornell Univ., Ithaca, NY (United States). Cornell High Energy Synchrotron Source (CHESS); Cornell Univ., Ithaca, NY (United States). Sibley School of Mechanical and Aerospace Engineering
Publication Date:
Report Number(s):
LLNL-JRNL-683851
Journal ID: ISSN 1359-6454
Grant/Contract Number:
AC52-07NA27344; AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 147; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Shear band; OFHC copper; X-ray diffraction; Crystal plasticity
OSTI Identifier:
1438793