Time, stress, and temperature-dependent deformation in nanostructured copper: Stress relaxation tests and simulations

doi:10.1016/j.actamat.2016.02.021

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	Time, stress, and temperature-dependent deformation in nanostructured copper: Stress relaxation tests and simulations
	Yang XS; Wang YJ(王云江); Wang GY; Zhai HR; Dai LH(戴兰宏); Zhang TY; Zhang, TY (reprint author), Shanghai Univ, Mat Genome Inst, 99 Shangda Rd, Shanghai 200444, Peoples R China.
发表期刊	ACTA MATERIALIA
	2016
卷号	108 页码:252-263
ISSN	1359-6454
摘要	In the present work, stress relaxation tests, high-resolution transmission electron microscopy (HRTEM), and molecular dynamics (MD) simulations were conducted on coarse-grained (cg), nanograined (ng), and nanotwinned (nt) copper at temperatures of 22 degrees C (RT), 30 degrees C, 40 degrees C, 50 degrees C, and 75 degrees C. The comprehensive investigations provide sufficient information for the building-up of a formula to describe the time, stress, and temperature-dependent deformation and clarify the relationship among the strain rate sensitivity parameter, stress exponent, and activation volume. The typically experimental curves of logarithmic plastic strain rate versus stress exhibited a three staged relaxation process from a linear high stress relaxation region to a subsequent nonlinear stress relaxation region and finally to a linear low stress relaxation region, which only showed-up at the test temperatures higher than 22 degrees C, 22 degrees C, and 30 degrees C, respectively, in the tested cg-, ng-, and nt-Cu specimens. The values of stress exponent, stress independent activation energy, and activation volume were determined from the experimental data in the two linear regions. The determined activation parameters, HRTEM images, and MD simulations consistently suggest that dislocation-mediated plastic deformation is predominant in all tested cg-, ng-, and nt-Cu specimens in the initial linear high stress relaxation region at the five relaxation temperatures, whereas in the linear low stress relaxation region, the grain boundary (GB) diffusion-associated deformation is dominant in the ng- and cg-Cu specimens, while twin boundary (TB) migration, i.e., twinning and detwinning with parallel partial dislocations, governs the time, stress, and temperature-dependent deformation in the nt-Cu specimens. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词	Stress Relaxation Nanotwin Copper Hrtem Atomistic Simulations
DOI	10.1016/j.actamat.2016.02.021
URL	查看原文
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000374072700024
关键词[WOS]	Stress relaxation ; Nanotwin ; Copper ; HRTEM ; Atomistic simulations
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 the General Research Fund (Project number, 622911) from the Hong Kong Research Grants Council. T.Y.Z. is grateful for the financial support by the research grant (No.14DZ2261200) from the Science and Technology Commission of Shanghai Municipality. Y.J.W and L.H.D acknowledge the financial supports from the NSFC (Nos. 11132011, 11402269, 11472287), the National Key Basic Research Program of China (No. 2012CB937500), and the CAS/SAFEA International Partnership Program for Creative Research Teams. G.Y. W thanks the National Nature Science Foundation (grant No. 51401083).
课题组名称	LNM冲击动力学与新型材料力学性能
论文分区	一类
力学所作者排名	False
引用统计	被引频次：64[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/311007/59507
专题	非线性力学国家重点实验室
通讯作者	Zhang, TY (reprint author), Shanghai Univ, Mat Genome Inst, 99 Shangda Rd, Shanghai 200444, Peoples R China.
推荐引用方式 GB/T 7714	Yang XS,Wang YJ,Wang GY,et al. Time, stress, and temperature-dependent deformation in nanostructured copper: Stress relaxation tests and simulations[J]. ACTA MATERIALIA,2016,108:252-263.
APA	Yang XS.,Wang YJ.,Wang GY.,Zhai HR.,Dai LH.,...&Zhang, TY .(2016).Time, stress, and temperature-dependent deformation in nanostructured copper: Stress relaxation tests and simulations.ACTA MATERIALIA,108,252-263.
MLA	Yang XS,et al."Time, stress, and temperature-dependent deformation in nanostructured copper: Stress relaxation tests and simulations".ACTA MATERIALIA 108(2016):252-263.

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