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Fatigue crack propagation properties of Ti-6Al-4V in vacuum environments
| Title: | Fatigue crack propagation properties of Ti-6Al-4V in vacuum environments |
| Authors: | Oguma, H. Browse this author | | Nakamura, T. Browse this author |
| Keywords: | Fatigue crack growth | | Sub-surface fracture | | Granular region | | Vacuum | | Titanium alloy |
| Issue Date: | May-2013 |
| Publisher: | Elsevier |
| Journal Title: | International Journal of Fatigue |
| Volume: | 50 |
| Start Page: | 89 |
| End Page: | 93 |
| Publisher DOI: | 10.1016/j.ijfatigue.2012.02.012 |
| Abstract: | To determine the effects of vacuum environment on fatigue crack propagations in a Ti-6Al-4V alloy, K-decreasing tests were conducted in air and vacuum. The fatigue crack propagation rate became slower and threshold stress intensity factor range became larger with decreasing vacuum pressure. The tendency cannot be fully explained by the crack closure. Based on fracture surface observations, granular region of a few micrometer size asperities was observed on the fracture surface only in high vacuum and ultra high vacuum. The high vacuum environment is one of the necessary conditions for the formation of the granular region, and the fraction of surface coverage of adsorbed gas on fracture surfaces relates to the phenomenon. The formation of the granular region represents the difference of the crack propagation mechanism between vacuum and air environments. A new mechanism for the formation of the granular region was proposed, and that is one of the phenomena which can explain the reduction of crack propagation rate in vacuum. (C) 2012 Elsevier Ltd. All rights reserved. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/53029 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 小熊 博幸
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