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

摘要: Abstract This paper is dedicated to the high cycle fatigue (HCF) behaviour of cast Al–Si alloys. In particular, three similar alloys with different microstructural characteristics are investigated. The result an experimental campaign presented, in order characterise behaviour, and more specifically damage mechanisms related heterogeneities (i.e. casting porosity, dendrite size, SDAS, non-metallic inclusions silicon particles), observed under multiaxial loading conditions: pure tension, plane bending, torsion combined tension–torsion a load ratio R=−1. It shown that porosity has very detrimental influence on uniaxial strengths. However, much lower for torsional strength. For porosity-free alloy, it formation persistent slip bands (PSB) aluminium matrix major crack initiation mechanism regardless modes, at also large role PSB Si particles facilitate PSB.