Influence of corrosion fatigue on the fatigue strength of an AlSi10MgMn high-pressure die-casting alloy with regard to the surface condition

This study investigates the influence of corrosion fatigue on the fatigue strength of an AlSi10MgMn high-pressure die-casting alloy with regard to the surface condition. Two different surface conditions are compared. First, an unmachined surface condition with a rough surface (μ) and second a machined and polished surface condition with a smooth, polished surface (μ) are tested. The specimens are loaded with a cyclic bending moment at a constant stress ratio of R = 0 till failure. A 5 wt% NaCl solution enables the corrosion fatigue tests. Corrosion fatigue leads to a significant reduction of the endurable stresses along the whole load spectrum independent from the surface condition. The applied corrosive solution prevents the formation of a pronounced long-life fatigue strength limit within the tested load cycle range. Hence, the reduction of the endurable stresses increases with the increasing number of load cycles, reaching approximately 37% at load cycles. No significant influence of the surface condition, independent of the environment (air, 5 wt% NaCl), on the fatigue behaviour is found.