Effect of temperature on silicon particle damage in A356 alloy

Abstract

The Al-Si-Mg base cast alloys are widely used for structural applications. Mechanical properties and fracture behavior of these alloys depend on macrodefects such as internal oxide layers and shrinkage macroporosity, microporosity, dendrite cell size, and size and shape of Si particles present in the interdendritic regions. Fracture and debonding of silicon particles is an important aspect of damage evolution in these alloys. Fracturing/debonding of silicon particles, formation and growth of voids around such particles, and subsequent interlinkage of the voids lead to crack propagation in the interdendritic regions. It is observed that silicon particles fracture/debond at stresses significantly below the ultimate tensile strength, but usually above yield stress of the material. There have been numerous studies on effect of tensile strain on the fraction of damaged particles in Al-Si-Mg base alloys. The damaged silicon particles are observed at very low plastic strain levels, and the fraction of damaged particles monotonically increases with the tensile strain. However, in the earlier investigations, the mechanical tests were performed at room temperature only. To the best of the authors` knowledge, no experimental data on the effect of temperature on the microstructural damage exist for Al-Si-Mg base cast alloys. Such experimental data are required formore » micro- and macromechanics based finite element simulations of cast components that experience temperature variations in service. It is the purpose of this communication to report quantitative data on the effect of temperature on the fraction of damaged silicon particles in a chill cast A356 alloy.« less