Atomistic tensile deformation mechanisms of Fe with gradient nano-grained structure

doi:10.1063/1.4928448

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	Atomistic tensile deformation mechanisms of Fe with gradient nano-grained structure
	Li, Wenbin; Yuan, Fuping; Wu, Xiaolei; Yuan, FP (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, 15,North 4th Ring,West Rd, Beijing 100190, Peoples R China.
发表期刊	AIP ADVANCES
	2015-08-01
卷号	5 期号:8 页码:87120
ISSN	2158-3226
摘要	Large-scale molecular dynamics (MD) simulations have been performed to investigate the tensile properties and the related atomistic deformation mechanisms of the gradient nano-grained (GNG) structure of bcc Fe (gradient grains with d from 25 nm to 105 nm), and comparisons were made with the uniform nano-grained (NG) structure of bcc Fe (grains with d = 25 nm). The grain size gradient in the nano-scale converts the applied uniaxial stress to multi-axial stresses and promotes the dislocation behaviors in the GNG structure, which results in extra hardening and flow strength. Thus, the GNG structure shows slightly higher flow stress at the early plastic deformation stage when compared to the uniform NG structure (even with smaller grain size). In the GNG structure, the dominant deformation mechanisms are closely related to the grain sizes. For grains with d = 25 nm, the deformation mechanisms are dominated by GB migration, grain rotation and grain coalescence although a few dislocations are observed. For grains with d = 54 nm, dislocation nucleation, propagation and formation of dislocation wall near GBs are observed. Moreover, formation of dislocation wall and dislocation pile-up near GBs are observed for grains with d = 105 nm, which is the first observation by MD simulations to our best knowledge. The strain compatibility among different layers with various grain sizes in the GNG structure should promote the dislocation behaviors and the flow stress of the whole structure, and the present results should provide insights to design the microstructures for developing strong-and-ductile metals. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.; Large-scale molecular dynamics (MD) simulations have been performed to investigate the tensile properties and the related atomistic deformation mechanisms of the gradient nano-grained (GNG) structure of bcc Fe (gradient grains with d from 25 nm to 105 nm), and comparisons were made with the uniform nano-grained (NG) structure of bcc Fe (grains with d = 25 nm). The grain size gradient in the nano-scale converts the applied uniaxial stress to multi-axial stresses and promotes the dislocation behaviors in the GNG structure, which results in extra hardening and flow strength. Thus, the GNG structure shows slightly higher flow stress at the early plastic deformation stage when compared to the uniform NG structure (even with smaller grain size). In the GNG structure, the dominant deformation mechanisms are closely related to the grain sizes. For grains with d = 25 nm, the deformation mechanisms are dominated by GB migration, grain rotation and grain coalescence although a few dislocations are observed. For grains with d = 54 nm, dislocation nucleation, propagation and formation of dislocation wall near GBs are observed. Moreover, formation of dislocation wall and dislocation pile-up near GBs are observed for grains with d = 105 nm, which is the first observation by MD simulations to our best knowledge. The strain compatibility among different layers with various grain sizes in the GNG structure should promote the dislocation behaviors and the flow stress of the whole structure, and the present results should provide insights to design the microstructures for developing strong-and-ductile metals. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.
DOI	10.1063/1.4928448
URL	查看原文
收录类别	SCI
语种	英语
WOS记录号	WOS:000360655900029
关键词[WOS]	MOLECULAR-DYNAMICS SIMULATION ; NANOCRYSTALLINE MATERIALS ; NANOSTRUCTURED METAL ; MAXIMUM STRENGTH ; DUCTILITY ; COPPER ; DISLOCATION ; PLASTICITY ; TOUGHNESS ; STEEL
WOS研究方向	Science & Technology - Other Topics ; Materials Science ; Physics
WOS类目	Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary ; Physics, Applied
项目资助者	The financial supports of this work were provided by the National Key Basic Research Program of China (2012CB932203 and 2012CB937500) and NSFC (11222224, 11472286, and 11021262). The simulations reported here were performed at Supercomputing Center of Chinese Academy of Sciences.
课题组名称	LNM材料介观力学性能的表征
论文分区	Q3
引用统计	被引频次：18[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/311007/55776
专题	非线性力学国家重点实验室
通讯作者	Yuan, FP (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, 15,North 4th Ring,West Rd, Beijing 100190, Peoples R China.
作者单位	Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China
推荐引用方式 GB/T 7714	Li, Wenbin,Yuan, Fuping,Wu, Xiaolei,et al. Atomistic tensile deformation mechanisms of Fe with gradient nano-grained structure[J]. AIP ADVANCES,2015,5,8,:87120.
APA	Li, Wenbin,Yuan, Fuping,Wu, Xiaolei,&Yuan, FP .(2015).Atomistic tensile deformation mechanisms of Fe with gradient nano-grained structure.AIP ADVANCES,5(8),87120.
MLA	Li, Wenbin,et al."Atomistic tensile deformation mechanisms of Fe with gradient nano-grained structure".AIP ADVANCES 5.8(2015):87120.

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