Finite Element Modelling of the Temperature Dependent Low Cycle Fatigue Damage Mechanism of an AlSi12 Type Alloy

Aluminium cast alloys are used for engine components, such as pistons and cylinder heads. The micromechanical properties of an AlSi12 cast alloy under monotonic and cyclic loadings are investigated. Therefore a microstructure-based two dimensional finite element model is generated. The characteristic shape of primary precipitates is analyzed and translated into an artificial microstructure. The quality of the generated microstructure is evaluated based on the stress distribution along the primary particle boundaries. The effect of the temperature dependent material behavior of the aluminium matrix is studied with respect to the resulting stress distribution along the particle boundaries. The results are discussed in terms of a possible change of fracture mechanisms from a brittle type fracture at low temperatures to an increasingly ductile fracture at high temperatures.