Effect of stress ratio on fatigue properties of a titanium alloy (TC17) in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) were investigated by electromagnetic and ultrasonic fatigue testing. The S-N curves at R=-1, 0.1,0.5 and 0.7 at 110Hz and 20kHz were obtained and discussed. The effects of frequency on fatigue strength was also investigated. It was concluded that the fatigue strength with 50% fatigue failure probability at R=0.1, 0.5 and 0.7 is lower to the Goodman line and shows a bilinear decreasing trend. Cleavage fracture of primary grains in the surface and interior initiation zone were observed. The formation of the facets induced by the basal or prismatic slips of the H.C.P grains decreased the fatigue strength with variation in mean stress.
Bibliographical noteNOTICE: this is the author’s version of a work that was accepted for publication in International Journal of Fatigue. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Fatigue, [VOL 93, ISSUE 2, (2016)] DOI: [DOI]
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- Titanium alloy
- High cycle fatigue
- Very high cycle fatigue
- Fatigue failure
- Mean stress