Micromechanical study of intragranular stress and strain partitioning in an additively manufactured AlSi10Mg alloy

Abstract

This study addresses the effect of a cellular-dendritic microstructure on the intragranular deformation behavior of an additively manufactured AlSi10Mg alloy. Experimental investigations have revealed the Al dendritic cells with a characteristic size of several hundred nanometers. The cells are decorated by a thin eutectic layer which consists of an aluminum matrix reinforced by silicon nanoparticles. Based on the experimental data, a set of micromechanical models are constructed and implemented in finite-element calculations. The constitutive behavior of an aluminum phase is described in terms of anisotropic elasticity to take into account the crystal lattice effects. Calculation results are analyzed and discussed with the main focus being placed on the effect of microstructure-resolved stress and strain partitioning between Al and Si phases. The silicon content is shown to impact the range of stress variation at the intragranular scale and the places of stress concentration in the Al phase. The eutectic layer behaves as a metal matrix composite where reinforcing silicon particles restrict deformation of the aluminum matrix.