Microstructure and mechanical properties at different length scales and strain rates of nanocrystalline tantalum produced by high-pressure torsion

doi:10.1016/j.actamat.2010.12.042

IMECH-IR > 非线性力学国家重点实验室

	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
发表期刊	Acta Materialia
	2011
卷号	59 期号:6 页码:2423-2436
ISSN	1359-6454
摘要	Fully 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.
关键词	Nanocrystalline 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
学科领域	Materials Science ; Metallurgy & Metallurgical Engineering
DOI	10.1016/j.actamat.2010.12.042
URL	查看原文
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000288568500017
关键词[WOS]	CENTERED-CUBIC METALS ; SEVERE PLASTIC-DEFORMATION ; NONEQUILIBRIUM GRAIN-BOUNDARIES ; HALL-PETCH BEHAVIOR ; TENSILE BEHAVIOR ; RATE SENSITIVITY ; ULTRAFINE GRAIN ; SHEAR BANDS ; UNIAXIAL COMPRESSION ; SCREW DISLOCATIONS
WOS研究方向	Materials Science ; Metallurgy & Metallurgical Engineering
WOS类目	Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
项目资助者	This 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.
课题组名称	LNM材料介观力学性能的表征
论文分区	一类
引用统计	被引频次：107[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/44940
专题	非线性力学国家重点实验室
通讯作者	Wei, Q (reprint author), Univ N Carolina, Dept Mech Engn & Engn Sci, 9201 Univ City Blvd, Charlotte, NC 28223 USA
推荐引用方式 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.

条目包含的文件		下载所有文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
SCI-J2011065.pdf（2092KB）			开放获取	--	浏览下载