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Stress ratio, temperature and microstructural effects on the fatigue crack propagation threshold of titanium alloys

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Date Issued:
1991
Summary:
This research investigated the effects of stress ratio, temperature and microstructure on the near-threshold fatigue crack growth characteristics of three differently processed titanium alloys. The materials investigated included one hot-worked Ti-6Al-2Sn-4Zr-2Mo alloy, one cast Ti-6Al-4V alloy and one cast Ti-6Al-2Sn-4Zr-2Mo alloy. It was found that overall crack closure could account for apparent differences in fatigue threshold for stress ratios up to about 0.7. Tests run at stress ratios of 0.9, however, showed a noticeably lower fatigue threshold. Crack closure was not able to account for differences due to elevated temperature. Fractographic evidence is also presented which shows the extremely beneficial effects of larger grain size on the fatigue threshold through crack branching, deflection and bifurcation.
Title: Stress ratio, temperature and microstructural effects on the fatigue crack propagation threshold of titanium alloys.
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Name(s): Dauven, Joseph R.
Florida Atlantic University, Degree grantor
Salivar, Gary C., Thesis advisor
Type of Resource: text
Genre: Electronic Thesis Or Dissertation
Issuance: monographic
Date Issued: 1991
Publisher: Florida Atlantic University
Place of Publication: Boca Raton, Fla.
Physical Form: application/pdf
Extent: 170 p.
Language(s): English
Summary: This research investigated the effects of stress ratio, temperature and microstructure on the near-threshold fatigue crack growth characteristics of three differently processed titanium alloys. The materials investigated included one hot-worked Ti-6Al-2Sn-4Zr-2Mo alloy, one cast Ti-6Al-4V alloy and one cast Ti-6Al-2Sn-4Zr-2Mo alloy. It was found that overall crack closure could account for apparent differences in fatigue threshold for stress ratios up to about 0.7. Tests run at stress ratios of 0.9, however, showed a noticeably lower fatigue threshold. Crack closure was not able to account for differences due to elevated temperature. Fractographic evidence is also presented which shows the extremely beneficial effects of larger grain size on the fatigue threshold through crack branching, deflection and bifurcation.
Identifier: 14772 (digitool), FADT14772 (IID), fau:11563 (fedora)
Collection: FAU Electronic Theses and Dissertations Collection
Note(s): College of Engineering and Computer Science
Thesis (M.S.E.)--Florida Atlantic University, 1991.
Subject(s): Titanium alloys--Fatigue--Testing
Materials--Fatigue--Testing
Held by: Florida Atlantic University Libraries
Persistent Link to This Record: http://purl.flvc.org/fcla/dt/14772
Sublocation: Digital Library
Use and Reproduction: Copyright © is held by the author, with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Use and Reproduction: http://rightsstatements.org/vocab/InC/1.0/
Host Institution: FAU
Is Part of Series: Florida Atlantic University Digital Library Collections.