Dislocation nucleation and evolution at the ferrite-cementite interface under cyclic loadings

doi:10.1016/j.actamat.2019.12.052

CORC > 力学研究所 > 中国科学院力学研究所 > 非线性力学国家重点实验室

	Dislocation nucleation and evolution at the ferrite-cementite interface under cyclic loadings
	Liang LW(梁伦伟)1,2; Wang YJ(王云江)1,2; Chen Y(陈艳)1,2; Wang HY(汪海英)1,2; Dai LH(戴兰宏)1,2
刊名	ACTA MATERIALIA
	2020-03-01
卷号	186 页码:267-277
关键词	Pearlitic steels Cyclic deformation Mechanical property Interfacial dislocation Molecular dynamics
ISSN号	1359-6454
DOI	10.1016/j.actamat.2019.12.052
通讯作者	Wang, Yun-Jiang(yjwang@imech.ac.cn) ; Dai, Lan-Hong(lhdai@lnm.imech.ac.cn)
英文摘要	Fatigue is of significant importance to the engineering applications of the structural materials. High-strength pearlite steel consisting of a ductile ferrite phase and a brittle cementite phase is a widely used structural metal for extreme load-bearing applications. However, the fatigue mechanisms of such important materials remain elusive, in particular, the atomic-scale dislocation behaviors at interface are poorly understood. We used molecular dynamics simulations to probe the mechanical response and deformation mechanism of the Bagaryatskii-oriented ferrite-cementite interface in pearlite. The interface was subjected to a hundred symmetric tension-compression deformation cycles. Three different loading schemes with strain magnitudes of 4.0%, 6.0%, and 9.0% are sophisticatedly designed to explore the cyclic plastic mechanisms under different conditions corresponding to pure elasticity, elasticity in tension but plasticity in compression, and plasticity in both tension and compression, respectively. During cyclic deformation, rapid dislocation accumulation occurs in the first 30 cycles, after which dislocation density decreases to a stable value in ferrite. It is found that the onset of plasticity is governed by dislocation nucleation from the ferrite-cementite interface. After slip into the ferrite phase, some dislocations annihilate at the interface. After a few tens of cycles, the dislocation nucleation and annihilation rates become equal, leading to a steady-state flow in cyclic deformation. Up to high cycles with large strain magnitude, the magnitude of plastic strain in pearlite is higher than critical values and slip crosses the interface from the ferrite phase to the brittle cementite phase. Dislocation slip in cementite will destroy the interface structure, which may be the plastic mechanism of final fatigue failure. Our simulations agree with experimental observations of dislocation evolution in the ratchetting of pearlitic steels and provide further atomic-scale mechanisms to explain the fatigue failure of these materials. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
分类号	一类
资助项目	National Key Research and Development Program of China[2017YFB0702003] ; National Key Research and Development Program of China[2017YFB0701502] ; NSFC[11790292] ; NSFC[11572324] ; NSFC[11672299] ; Strategic Priority Research Program[XDB22040302] ; Strategic Priority Research Program[XDB22040303] ; Key Research Program of Frontier Sciences[QYZDISSW-JSC011] ; Youth Innovation Promotion Association of the Chinese Academy of Sciences[2017025]
WOS关键词	SLIP TRANSFER MECHANISMS ; 316L STAINLESS-STEEL ; PEARLITIC STEEL ; FERRITE/CEMENTITE INTERFACE ; MOLECULAR-DYNAMICS ; CARBON-STEELS ; DEFORMATION MECHANISMS ; PLASTIC-DEFORMATION ; BEHAVIOR ; FRACTURE
WOS研究方向	Materials Science ; Metallurgy & Metallurgical Engineering
语种	英语
WOS记录号	WOS:000518698300025
资助机构	National Key Research and Development Program of China ; NSFC ; Strategic Priority Research Program ; Key Research Program of Frontier Sciences ; Youth Innovation Promotion Association of the Chinese Academy of Sciences
其他责任者	Wang, Yun-Jiang ; Dai, Lan-Hong
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/81825]
专题	力学研究所_非线性力学国家重点实验室
作者单位	1.Univ Chinese Acad Sci, Sch Engn Sci, Beijing 101408, Peoples R China 2.Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China;
推荐引用方式 GB/T 7714	Liang LW,Wang YJ,Chen Y,et al. Dislocation nucleation and evolution at the ferrite-cementite interface under cyclic loadings[J]. ACTA MATERIALIA,2020,186:267-277.
APA	梁伦伟,王云江,陈艳,汪海英,&戴兰宏.(2020).Dislocation nucleation and evolution at the ferrite-cementite interface under cyclic loadings.ACTA MATERIALIA,186,267-277.
MLA	梁伦伟,et al."Dislocation nucleation and evolution at the ferrite-cementite interface under cyclic loadings".ACTA MATERIALIA 186(2020):267-277.