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Title: Quantifying heterogeneous deformation in grain boundary regions on shock loaded tantalum using spherical and sharp tip nanoindentation

Abstract

Grain boundaries play an important role in the overall mechanical performance of metals and alloys; however, isolating the effects of individual grain boundaries remains rather challenging experimentally. In this work, wire-feed, electron beam additively manufactured tantalum is studied under shock loading conditions generating incipient spall damage. Three grain boundaries aligned parallel to the shock direction were isolated inside a single sample. Postmortem metallography showed voids preferentially appeared on two of the three grain boundaries which had high misorientation angles > 30° compared to the third grain boundary with a relatively lower misorientation angle < 10°. Nanoindentation in grain boundary regions for both pyramidal and spherical tips showed characteristically different strain hardening trends for each grain boundary. Significant local strain hardening is present on both sides of one high angle grain boundary, while strain softening is captured at the other high angle grain boundary. A negligible trend of either hardening or softening is shown in the vicinity of the single low angle grain boundary. As a result, this leads to the conclusion that the trend of strain hardening/softening in grain boundary regions is not monotonically correlated to the susceptibility of specific grain boundaries to an increased propensity for void damage.

Authors:
 [1]; ORCiD logo [1]; ORCiD logo [1];  [2]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Minnesota-Twin Cities, Minneapolis, MN (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1477707
Report Number(s):
LA-UR-18-29241
Journal ID: ISSN 0921-5093
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Accepted Manuscript
Journal Name:
Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing
Additional Journal Information:
Journal Volume: 737; Journal Issue: C; Journal ID: ISSN 0921-5093
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Spall; Hardness; Dynamic deformation; Grains and interfaces; Stress/strain measurements; Electron microscopy

Citation Formats

Weaver, Jordan S., Jones, David Robert, Li, Nan, Mara, Nathan, Fensin, Saryu Jindal, and Gray, III, George Thompson. Quantifying heterogeneous deformation in grain boundary regions on shock loaded tantalum using spherical and sharp tip nanoindentation. United States: N. p., 2018. Web. doi:10.1016/j.msea.2018.09.075.
Weaver, Jordan S., Jones, David Robert, Li, Nan, Mara, Nathan, Fensin, Saryu Jindal, & Gray, III, George Thompson. Quantifying heterogeneous deformation in grain boundary regions on shock loaded tantalum using spherical and sharp tip nanoindentation. United States. doi:10.1016/j.msea.2018.09.075.
Weaver, Jordan S., Jones, David Robert, Li, Nan, Mara, Nathan, Fensin, Saryu Jindal, and Gray, III, George Thompson. Fri . "Quantifying heterogeneous deformation in grain boundary regions on shock loaded tantalum using spherical and sharp tip nanoindentation". United States. doi:10.1016/j.msea.2018.09.075. https://www.osti.gov/servlets/purl/1477707.
@article{osti_1477707,
title = {Quantifying heterogeneous deformation in grain boundary regions on shock loaded tantalum using spherical and sharp tip nanoindentation},
author = {Weaver, Jordan S. and Jones, David Robert and Li, Nan and Mara, Nathan and Fensin, Saryu Jindal and Gray, III, George Thompson},
abstractNote = {Grain boundaries play an important role in the overall mechanical performance of metals and alloys; however, isolating the effects of individual grain boundaries remains rather challenging experimentally. In this work, wire-feed, electron beam additively manufactured tantalum is studied under shock loading conditions generating incipient spall damage. Three grain boundaries aligned parallel to the shock direction were isolated inside a single sample. Postmortem metallography showed voids preferentially appeared on two of the three grain boundaries which had high misorientation angles > 30° compared to the third grain boundary with a relatively lower misorientation angle < 10°. Nanoindentation in grain boundary regions for both pyramidal and spherical tips showed characteristically different strain hardening trends for each grain boundary. Significant local strain hardening is present on both sides of one high angle grain boundary, while strain softening is captured at the other high angle grain boundary. A negligible trend of either hardening or softening is shown in the vicinity of the single low angle grain boundary. As a result, this leads to the conclusion that the trend of strain hardening/softening in grain boundary regions is not monotonically correlated to the susceptibility of specific grain boundaries to an increased propensity for void damage.},
doi = {10.1016/j.msea.2018.09.075},
journal = {Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing},
number = C,
volume = 737,
place = {United States},
year = {2018},
month = {9}
}

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