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

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	Atomistic tensile deformation mechanisms of Fe with gradient nano-grained structure
	Li, Wenbin; Yuan, Fuping; Wu, Xiaolei
刊名	AIP ADVANCES
	2015-08-01
通讯作者邮箱	fpyuan@lnm.imech.ac.cn
卷号	5 期号:8 页码:87120
ISSN号	2158-3226
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.
产权排序	[Li, Wenbin; Yuan, Fuping; Wu, Xiaolei] Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China
中文摘要	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.
英文摘要	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.
分类号	Q3
类目[WOS]	Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary ; Physics, Applied
研究领域[WOS]	Science & Technology - Other Topics ; Materials Science ; Physics
关键词[WOS]	MOLECULAR-DYNAMICS SIMULATION ; NANOCRYSTALLINE MATERIALS ; NANOSTRUCTURED METAL ; MAXIMUM STRENGTH ; DUCTILITY ; COPPER ; DISLOCATION ; PLASTICITY ; TOUGHNESS ; STEEL
收录类别	SCI
原文出处	http://dx.doi.org/10.1063/1.4928448
语种	英语
WOS记录号	WOS:000360655900029
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/55776]
专题	力学研究所_非线性力学国家重点实验室
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. 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.(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.