Effects of stress ratio on high-cycle and very-high-cycle fatigue behavior of a Ti-6Al-4V alloy

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	Effects of stress ratio on high-cycle and very-high-cycle fatigue behavior of a Ti-6Al-4V alloy
	Liu XL(刘小龙); Sun CQ(孙成奇); Hong YS(洪友士)
刊名	MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
	2015-01-12
通讯作者邮箱	hongys@imech.ac.cn
卷号	622 页码:228-235
关键词	Ti-6Al-4V alloy Stress ratio Crack initiation type Crack growth threshold Very-high-cycle fatigue
ISSN号	0921-5093
通讯作者	Hong, YS (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China.
产权排序	[Liu, Xiaolong; Sun, Chengqi; Hong, Youshi] Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China
合作状况	国内
中文摘要	The effects of stress ratio on high-cycle fatigue (HCF) and very-high-cycle fatigue (VHCF) behavior of a Ti-6Al-4V alloy were systematically investigated in this paper. Fatigue tests with ultrasonic frequency (20 kHz) were performed on specimens of a bimodal Ti-6Al-4V alloy with stress ratios of -1, -0.5, -0.1, 0.1 and 0.5. Three types of crack initiation mode were observed on the fracture surfaces of the specimens that failed in the HCF and the VHCF regimes, which were explicitly classified as surface-without-facets, surface-with-facets and interior-with-facets. With the increase of stress ratio from 1 to 0.5, the number of specimens for surface-without-facets decreased, that for surface-with-facets increased, and that for interior-with-facets increased first and then decreased. For the failure types of surface-with-facets and interior-with-facets, the fatigue strength decreased sharply in the VHCF regime, and the S-N curve switched from an asymptote shape to a duplex shape. Then, a new model based on Poisson defect distribution was proposed to describe the effects of stress ratio on the occurrence of different failure types, i.e., the competition of alternative failure types. The observations also showed that there is a rough area at the crack initiation region for interior initiation cases, and the values of the stress intensity factor range for the rough area are within a small range, with the mean value being close to the threshold for the crack starting to grow in vacuum environment of the alloy. The estimated value of plastic zone size at the periphery of rough area is close to the average diameter of the primary cc grains of the alloy. (C) 2014 Elsevier B.V. All rights reserved.
学科主题	Science & Technology - Other Topics ; Materials Science ; Metallurgy & Metallurgical Engineering
分类号	一类
收录类别	SCI ; EI
资助信息	The financial supports by the National Basic Research Program of China (2012CB937500) and by the National Natural Science Foundation of China (11202210, 11172304 and 11021262) are gratefully appreciated.
原文出处	http://dx.doi.org/10.1016/j.msea.2014.09.115
语种	英语
WOS记录号	WOS:000348957400031
公开日期	2015-03-17
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/49610]
专题	力学研究所_非线性力学国家重点实验室
推荐引用方式 GB/T 7714	Liu XL,Sun CQ,Hong YS. Effects of stress ratio on high-cycle and very-high-cycle fatigue behavior of a Ti-6Al-4V alloy[J]. MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING,2015,622:228-235.
APA	Liu XL,Sun CQ,&Hong YS.(2015).Effects of stress ratio on high-cycle and very-high-cycle fatigue behavior of a Ti-6Al-4V alloy.MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING,622,228-235.
MLA	Liu XL,et al."Effects of stress ratio on high-cycle and very-high-cycle fatigue behavior of a Ti-6Al-4V alloy".MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING 622(2015):228-235.