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Microstructure and mechanical properties at different length scales and strain rates of nanocrystalline tantalum produced by high-pressure torsion
Wei Q; Pan ZL; Wu XL(武晓雷); Schuster BE; Kecskes LJ; Valiev RZ; Wei, Q (reprint author), Univ N Carolina, Dept Mech Engn & Engn Sci, 9201 Univ City Blvd, Charlotte, NC 28223 USA
Source PublicationActa Materialia
2011
Volume59Issue:6Pages:2423-2436
ISSN1359-6454
AbstractFully dense, nanocrystalline tantalum (average grain size as small as similar to 40 nm) has been processed for the first time by high-pressure torsion. High-resolution transmission electron microscopy reveals non-equilibrium grain boundaries and grains decorated with high-density dislocations. Microhardness measurements and instrumented nanoindentation experiments indicate that the mechanical property is quite uniform except for the central area of the disks. Nanoindentation experiments at different strain rates suggest that the strain rate sensitivity of nanocrystalline tantalum is increased compared to the coarse- and ultrafine-grained counterparts and is accompanied by an activation energy of the order of a few similar to b(3) (b is the magnitude of the dislocation Burgers vector), implying a shift in the plastic deformation mechanism from the screw dislocation dominated regime. We thus infer the plastic deformation mechanisms of nanocrystalline body-centered cubic (bcc) and face-centered cubic metals converge. To examine the stress strain behavior, we have used microcompression to measure the compressive stress strain curves on microscale pillars fabricated by focused ion beam technique. Yield strength as high as 1.6 GPa has been observed. High-strain rate behavior has been investigated using a miniature Kolsky bar system. We have found that at high-strain rates the nanocrystalline tantalum specimens exhibit adiabatic shear banding, a dynamic plastic deformation mode common to many ultrafine-grained and all nanocrystalline bcc metals. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
KeywordNanocrystalline Tantalum Microstructure Mechanical Properties Adiabatic Shear Band Centered-cubic Metals Severe Plastic-deformation Nonequilibrium Grain-boundaries Hall-petch Behavior Tensile Behavior Rate Sensitivity Ultrafine Grain Shear Bands Uniaxial Compression Screw Dislocations
Subject AreaMaterials Science ; Metallurgy & Metallurgical Engineering
DOI10.1016/j.actamat.2010.12.042
URL查看原文
Indexed BySCI ; EI
Language英语
WOS IDWOS:000288568500017
WOS KeywordCENTERED-CUBIC METALS ; SEVERE PLASTIC-DEFORMATION ; NONEQUILIBRIUM GRAIN-BOUNDARIES ; HALL-PETCH BEHAVIOR ; TENSILE BEHAVIOR ; RATE SENSITIVITY ; ULTRAFINE GRAIN ; SHEAR BANDS ; UNIAXIAL COMPRESSION ; SCREW DISLOCATIONS
WOS Research AreaMaterials Science ; Metallurgy & Metallurgical Engineering
WOS SubjectMaterials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
Funding OrganizationThis work was supported by US Army Research Laboratory under Contract # W911QX-06-C-0124. The authors would like to thank Mr. W.H. Yin for assistance in some experiments. They are also indebted to Drs. Z.G. Xu and S. Yarmolenko at NC A&T State University for assistance with microhardness, nanoindentation and XRD measurement. X.L.W. acknowledges the support of NSFC Grant Nos. 11021262, 11072243, and 973 Project Grants Nos. 2010CB631004 and 2009CB623700.
DepartmentLNM材料介观力学性能的表征
Classification一类
Citation statistics
Cited Times:77[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://dspace.imech.ac.cn/handle/311007/44940
Collection非线性力学国家重点实验室
Corresponding AuthorWei, Q (reprint author), Univ N Carolina, Dept Mech Engn & Engn Sci, 9201 Univ City Blvd, Charlotte, NC 28223 USA
Recommended Citation
GB/T 7714
Wei Q,Pan ZL,Wu XL,et al. Microstructure and mechanical properties at different length scales and strain rates of nanocrystalline tantalum produced by high-pressure torsion[J]. Acta Materialia,2011,59(6):2423-2436.
APA Wei Q.,Pan ZL.,武晓雷.,Schuster BE.,Kecskes LJ.,...&Wei, Q .(2011).Microstructure and mechanical properties at different length scales and strain rates of nanocrystalline tantalum produced by high-pressure torsion.Acta Materialia,59(6),2423-2436.
MLA Wei Q,et al."Microstructure and mechanical properties at different length scales and strain rates of nanocrystalline tantalum produced by high-pressure torsion".Acta Materialia 59.6(2011):2423-2436.
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