Role of eutectic silicon particles in fatigue crack initiation and propagation and fatigue strength characteristics of cast aluminum alloy A356

•We study the role of the eutectic silicon particle on fatigue characteristics of Al–Si aluminum alloy.•We conduct a fatigue test with cast aluminum alloy A356.•The behavior of fatigue crack initiation is different in the LCF and the HCF regimes.•A small fatigue life scatter is the characteristic of the tested alloy.•The fatigue crack propagation limit is absent in the tested alloy evaluated by using a plain specimen.

The cast aluminum alloy A356 was studied to observe the effects of the eutectic silicon particles on its fatigue strength characteristics and the initiation and propagation of fatigue cracks. Two mechanisms of the initiation of the fatigue cracks were observed in the low-cycle fatigue regime, and only one in the high-cycle fatigue regime. A small fatigue life scatter was also found to be characteristics of the specimens of the alloys. Furthermore, the existence of a fatigue limit in the alloy is discussed.