Variable amplitude loading of spray‐formed hypereutectic aluminium silicon alloy DISPAL® S232 in the VHCF regime

• DOI: 10.1111/ffe.12178
• Publication Date: 2014-03-19T13:16:47Z
• Authors: M. Fitzka; H. Mayer; R. Schuller; S. E. Stanzl‐Tschegg; T. Przeorski; P. Krug
• Keywords: Tension (geology); Paris' law

ABSTRACT Spray‐formed hypereutectic aluminium silicon alloy DISPAL® S232–T6x is cycled with variable amplitude at ultrasonic frequency up to the very high cycle fatigue (VHCF) regime under fully reversed tension–compression loading. The Powder Metallurgy tested using a Gaussian cumulative distribution of load cycles, and lifetimes are compared constant data. Miner calculation delivers mean damage sums between 0.5 0.9 for 8 × 10 7 1.6 respectively. Cracks initiated voids, inclusions or distributed inhomogeneities (porous areas oxides) surface in interior. In situ analysis vibration properties indicates that cracks formed start growing from beginning cycling, even if failure occurs regime. Crack initiation stage negligible. Lifetime prediction performed an adapted Paris‐law considering lifetime as cycles necessary propagate initial crack failure. Measured predicted differ by factor 0.4–1.0. Large crack‐initiating defects strongly reduce lifetimes, which successfully covered propagation model.