On the impact toughness of gradient-structured metals

doi:10.1016/j.actamat.2020.04.027

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	On the impact toughness of gradient-structured metals
	Lin, Yan 1,3; Yu, Qin 2; Pan, Jie 1; Duan, Fenghui 1; Ritchie, Robert O.2; Li, Yi 1
刊名	ACTA MATERIALIA
	2020-07-01
卷号	193 页码:125-137
关键词	Gradient structures Grain-size gradients Impact toughness Dynamic J-R curves Nickel
ISSN号	1359-6454
DOI	10.1016/j.actamat.2020.04.027
通讯作者	Pan, Jie(jiepan@imr.ac.cn) ; Ritchie, Robert O.(roritchie@lbl.gov) ; Li, Yi(liyi@imr.ac.cn)
英文摘要	Gradient-structured (GS) materials are capable of displaying high strength without compromising ductility, which can result in damage-tolerant structures. However, due to the difficulties in fabricating bulk GS materials, there has been only limited studies on the fracture behavior in GS metals. In the present work, the impact toughness of the macroscale GS pure Ni plates was investigated using instrumented Charpy impact testing. The gradient orientation was found to have a significant influence on the impact toughness of GS Ni. For gradient structures that transition from coarse grains (CG) to nano-grains (NG), termed CG -> NG gradients (in the present study from similar to 8 mu m to similar to 30 nm), the absorbed energy and the tensile strength were increased, respectively, by 1.6 and 2.3 times from those exhibited by uniformcoarse-grained structures, demonstrating a simultaneous enhancement in strength and impact toughness. Analysis of load-displacement curves revealed that the resistance to both crack initiation and propagation were significantly enhanced as the crack penetrated through the CG -> NG gradient structure, leading to markedly rising dynamic R-curve behavior estimated from nonlinearelastic fracture mechanics J-based measurements. The superior fracture resistance in the CG -> NG gradient structure was found to originate from sustained ductile fracture by microvoid coalescence, taking place not only in the initial CG zone, but also within the latter NG regions where adiabatic shear bands form during impact; in these latter regions, plasticity becomes enhanced due to grain coarsening induced by recrystallization under the dynamic loading. The present work not only reveals how the dynamic fracture resistance can be significantly enhanced in GS metals, but also provides structure-design strategies for developing superior metallic materials for impact engineering applications. (C) 2020 ActaMaterialia Inc. Published by Elsevier Ltd. All rights reserved.
资助项目	National Key Research and Development Program of China[2017YFB0702003] ; National Natural Science Foundation of China[51471165] ; National Natural Science Foundation of China[51871217]
WOS研究方向	Materials Science ; Metallurgy & Metallurgical Engineering
语种	英语
出版者	PERGAMON-ELSEVIER SCIENCE LTD
WOS记录号	WOS:000540707100012
资助机构	National Key Research and Development Program of China ; National Natural Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/139330]
专题	金属研究所_中国科学院金属研究所
通讯作者	Pan, Jie; Ritchie, Robert O.; Li, Yi
作者单位	1.Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China 2.Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA 3.Univ Chinese Acad Sci, 19 Yuquan Rd, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Lin, Yan,Yu, Qin,Pan, Jie,et al. On the impact toughness of gradient-structured metals[J]. ACTA MATERIALIA,2020,193:125-137.
APA	Lin, Yan,Yu, Qin,Pan, Jie,Duan, Fenghui,Ritchie, Robert O.,&Li, Yi.(2020).On the impact toughness of gradient-structured metals.ACTA MATERIALIA,193,125-137.
MLA	Lin, Yan,et al."On the impact toughness of gradient-structured metals".ACTA MATERIALIA 193(2020):125-137.