Quantitative relationship between microstructure characteristics and fatigue parameters of A319 casting alloy

Abstract

Abstract This paper describes a microstructure‐based uniaxial strain‐controlled fatigue life prediction model applied to A319 aluminum alloy which is widely used in automobile industry. The materials made with different casting conditions are characterized and quantified in terms of secondary dendrite arm spacing (SDAS), size, and aspect ratio of eutectic Si particles. Uniaxial low cycle fatigue tests have been performed on four groups of A319 alloy under different casting conditions in which cooling rate and Sr addition are variables. It is shown that the effect of various degrees of microstructure on the fatigue life and fatigue behavior is obvious. The first part of the paper is quantitatively characterizing the microstructure of samples to identify the influence of different casting conditions. With regard to mechanic properties, the tensile properties and fatigue behavior of samples are analyzed combining with microstructure. Finally, a microstructure‐based Manson‐Coffin‐Basquin model is proposed to predict fatigue life of Al‐Si alloy.