Multiaxial high cycle fatigue damage mechanisms associated with the different microstructural heterogeneities of cast aluminium alloys

For the porosity-free alloy, it is observed that the formation of persistent slip bands (PSB) in the aluminium matrix is the major fatigue crack initiation mechanism regardless of the loading modes, at a load ratio of R=−1. It is also shown that the aluminium matrix has a large role in the formation of PSB and that the Si particles facilitate the formation of PSB.