Local mechanical properties in aluminum cast components are inhomogeneous as a con- sequence of spatial distribution of microstructure, e.g., porosity, inclusions, grain size and arm spacing of secondary dendrites. In...Local mechanical properties in aluminum cast components are inhomogeneous as a con- sequence of spatial distribution of microstructure, e.g., porosity, inclusions, grain size and arm spacing of secondary dendrites. In this work, the effect of porosity is investigated. Cast components contain voids with different sizes, forms, orientations and distributions. This is approximated by a porosity distribution in the following. The aim of this paper is to in- vestigate the influence of initial porosity, stress triaxiality and Lode parameter on plastic deformation and ductile fracture. A micromechanical model with a spherical void located at the center of the matrix material, called the representative volume element （RVE）, is de- veloped. Fully periodic boundary conditions are applied to the RVE and the values of stress triaxiality and Lode parameter are kept constant during the entire course of loading. For this purpose, a multi-point constraint （MPC） user subroutine is developed to prescribe the loading. The results of the RVE model are used to establish the constitutive equations and to further investigate the influences of initial porosity, stress triaxiality and Lode parameter on elastic constant, plastic deformation and ductile fracture of an aluminum die castin~ alloy.展开更多
基金supported in part by the National Natural Scientific Foundation of China(Fund Nos.11472085 and 11632007)the Guangxi Graduate Education Innova tion Project(Fund No.YCBZ2013010)+1 种基金funded with budget funds of the Federal Ministry of Eco nomics and Technology(BMWi)via the German Federation of Industrial Research Associations“Otto von Guericke”e.V.(AiF)(IGF-Nr.:412 ZN/1)supported by the Research Association of Automotive Technology(FAT)
文摘Local mechanical properties in aluminum cast components are inhomogeneous as a con- sequence of spatial distribution of microstructure, e.g., porosity, inclusions, grain size and arm spacing of secondary dendrites. In this work, the effect of porosity is investigated. Cast components contain voids with different sizes, forms, orientations and distributions. This is approximated by a porosity distribution in the following. The aim of this paper is to in- vestigate the influence of initial porosity, stress triaxiality and Lode parameter on plastic deformation and ductile fracture. A micromechanical model with a spherical void located at the center of the matrix material, called the representative volume element （RVE）, is de- veloped. Fully periodic boundary conditions are applied to the RVE and the values of stress triaxiality and Lode parameter are kept constant during the entire course of loading. For this purpose, a multi-point constraint （MPC） user subroutine is developed to prescribe the loading. The results of the RVE model are used to establish the constitutive equations and to further investigate the influences of initial porosity, stress triaxiality and Lode parameter on elastic constant, plastic deformation and ductile fracture of an aluminum die castin~ alloy.
