Walker parameter for mean stress correction in fatigue testing of Al-7%Si-Mg alloy castings

Hüseyin Özdeş, University of North Florida
Murat Tiryakioğlu, University of North Florida


In this study, performance of two existingWalker parameter estimation models has been investigated. Results show that those developed mainly for steel did not provide reasonable fits to experimentalWalker parameters for fatigue data for Al-7%Si-Mg alloy castings in the literature. A strong relationship between the Walker parameter and the structural quality, quantified by the quality index, QT, was observed and an empirical equation to estimate the Walker parameter for these alloys was developed. These findings indicate that the Walker parameter is not an intrinsic material property and the structural quality of the specimens must be taken into account for mean stress correction in fatigue testing.