EFFECTS OF MICROSTRUCTURE AND STRESS RATIO ON HIGH-CYCLE AND VERY-HIGH-CYCLE FATIGUE BEHAVIOR OF Ti-6Al-4V ALLOY | |
Liu XL![]() ![]() ![]() | |
Source Publication | ACTA METALLURGICA SINICA
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2016 | |
Volume | 52Issue:8Pages:923-930 |
ISSN | 0412-1961 |
Abstract | Titanium alloys have been widely used as superior engineering materials because of their high specific strength, high temperature resistance and high corrosion resistance. In their engineering applications such as used in aircraft engines, titanium alloys may experience even 10(10) fatigue cycles. Recently, faceted crack initiation was observed in high-cycle fatigue (HCF) and very-high-cycle fatigue (VHCF) regimes of titanium alloys, which resulted in a sharp decrease in fatigue strength. Therefore, the HCF and VHCF of titanium alloys have both scientific significance and engineering requirement. In this work, the effects of microstructure and stress ratio (R) on HCF and VHCF of a Ti-6Al-4V alloy have been investigated. Fatigue tests were conducted on a rotating-bending fatigue machine and an ultrasonic fatigue machine. All the fatigue fracture surfaces were observed by SEM. The results show that the HCF and VHCF behaviors of the fully-equiaxed and the bimodal Ti-6Al-4V alloy are similar. The observations of fracture surface indicate that two crack initiation mechanisms prevail, i.e. slip mechanism and cleavage mechanism. With the increase of stress ratio, the crack initiation mechanism switches from slip to cleavage. The S-N curves present the single-line type or the bilinear type. For the cases of rotating-bending and ultrasonic axial cycling with R= -1.0, -0.5 and 0.5, the S-N curves are single-line type corresponding to the slip mechanism or cleavage mechanism. For the cases of R= -0.1 and 0.1, the S-N curves are bilinear type corresponding to both slip and cleavage mechanisms. A model based on fatigue life and fatigue limit is proposed to describe the competition between the two mechanisms, which is in agreement with the experimental results. |
Keyword | Ti-6al-4v Alloy Very-high-cycle Fatigue Microstructure Stress Ratio Slip Mechanism Cleavage Mechanism |
DOI | 10.11900/0412.1961.2015.00581 |
URL | 查看原文 |
Indexed By | SCI ; EI |
Language | 英语 |
WOS ID | WOS:000381541900004 |
WOS Keyword | Ti-6Al-4V alloy ; very-high-cycle fatigue ; microstructure ; stress ratio ; slip mechanism ; cleavage mechanism |
WOS Research Area | Metallurgy & Metallurgical Engineering |
WOS Subject | Metallurgy & Metallurgical Engineering |
Funding Organization | Supported by National Natural Science Foundation of China (Nos.11202210 and 11572325) |
Department | LNM金属材料微结构与力学性能 |
Classification | 二类 |
Ranking | True |
Citation statistics | |
Document Type | 期刊论文 |
Identifier | http://dspace.imech.ac.cn/handle/311007/59745 |
Collection | 非线性力学国家重点实验室 |
Corresponding Author | Hong, YS (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China. |
Recommended Citation GB/T 7714 | Liu XL,Sun CQ,Zhou YT,et al. EFFECTS OF MICROSTRUCTURE AND STRESS RATIO ON HIGH-CYCLE AND VERY-HIGH-CYCLE FATIGUE BEHAVIOR OF Ti-6Al-4V ALLOY[J]. ACTA METALLURGICA SINICA,2016,52(8):923-930. |
APA | Liu XL,孙成奇,Zhou YT,洪友士,&Hong, YS .(2016).EFFECTS OF MICROSTRUCTURE AND STRESS RATIO ON HIGH-CYCLE AND VERY-HIGH-CYCLE FATIGUE BEHAVIOR OF Ti-6Al-4V ALLOY.ACTA METALLURGICA SINICA,52(8),923-930. |
MLA | Liu XL,et al."EFFECTS OF MICROSTRUCTURE AND STRESS RATIO ON HIGH-CYCLE AND VERY-HIGH-CYCLE FATIGUE BEHAVIOR OF Ti-6Al-4V ALLOY".ACTA METALLURGICA SINICA 52.8(2016):923-930. |
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