PNNL

Abstract

In this paper, a two-dimensional (2D) microstructure-based modeling method is developed in order to predict the ductility of a thin-walled high pressure die cast magnesium (Mg) by considering the three-dimensional (3D) thru-thickness pore distributions. For this purpose, a series of 3D synthetic microstructure-based finite element models as well as the corresponding 2D models are first generated with various pore volume fractions, pore size distributions and pore shapes. The input properties for the 2D models are determined based on the 3D cubic model with a spherical pore and the generalized Neuber’s rule. Based on the resulting ductility of the 3D and 2D models, a possible 3D/2D ductility correlation curve is obtained as function of the characteristics of the input fracture strain curve for the 3D model. The validity of the obtained ductility correlation curve is examined with actual sample microstructures measured by scanning acoustic microscopy. The results show that the suggested 2D modeling methodology can be used together with the ductility correlation curve in predicting the ductility of 3D models of thin-walled Mg castings. The suggested methodology may provide a basis for establishing possible 3D/2D fracture strain correlation curve for other loading conditions.