SEDL / STP / STP1360-EB / STP13404S

Fatigue Crack Propagation and Load Interaction Effects in a Titanium Alloy

Lang, M
National Research Council-Associate, Air Force Research Laboratory, Materials and Manufacturing DirectorateIABG, Wright-Patterson Air Force BaseOttobrunn, OH

Larsen, JM
Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH

Pages: 13    Published: Jan 2000

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Abstract

An experimental investigation of load interaction effects in Ti-6Al-2Sn-4Zn-2Mo is presented. Simple variable amplitude loading spectra were applied to test samples, and the crack propagation stress intensity factor, K^PR, was subsequently measured. The data were condensed to two equations (“master curves”) that describe the influence of an unloading cycle after constant amplitude loading and a single overload cycle, respectively. The results suggest that load interaction effects are caused by residual compressive stresses ahead of the crack front, whereas the influence of crack closure is minor.