Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7171456 | International Journal of Fatigue | 2018 | 30 Pages |
Abstract
In this paper experimental correlations between da/dN and ÎK and between a vs. N of an extra-low-interstitial titanium (Ti-6Al-4V ELI) alloy under four typical overload conditions (OL, UL, OL-UL and UL-OL) in an otherwise constant amplitude loading were obtained. By means of the digital image correlation (DIC) technique, the crack-tip deformation fields as well as the crack opening process corresponding to the four overloading patterns were measured. The results shown that both the crack propagation behaviors and the crack-tip strain distributions of the Ti-alloy were greatly influenced by the overloading conditions applied. The effect of the overloading pattern (sequence) on the fatigue crack propagation behavior of the Ti-alloy was then analyzed by combining the crack-tip deformation measurements with the fatigue crack propagation results from three possible mechanisms, i.e., the crack-tip blunting effect, the crack closure effect and crack-tip plastic zone effect. It was found that for the present investigated Ti-6Al-4V ELI alloy, the above three mechanisms made contributions in different extents to the fatigue crack growth retardation behavior.
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Authors
Chuanyong Chen, Duyi Ye, Lina Zhang, Jianzhong Liu,