Micromechanical Modeling of the Static Loading of an Al 359-SiC MMC

Abstract

The objective of this work was to use micromechanical finite element models to simulate the static mechanical behavior of a metal matrix composite: a cast Al 359 alloy reinforced with 20% SiC particles, at two different temperatures: room temperature and 150°C. In the simulations, periodic unit cell models incorporating the explicit representation of the matrix, reinforcing particles and precipitated primary silicon crystals in both 2D and 3D were used. Micromechanical models with both idealized and realistic reinforcing particle geometries and distributions were generated. The realistic particle geometries and distributions were inferred from experimental SEM micrographs. The pattern and intensity of the plastic deformation within the matrix was studied and the macroscale behavior of the composite was inferred from average stress and strain values. In order to include the effects of residual stresses due to the processing of the material, a quenching simulation was performed, prior to mechanical loading, and its effects on the macroscopic and microscopic behavior of the MMC was assessed. The effects of introducing the damage mechanisms of ductile void growth and brittle failure of the reinforcing particles was also investigated. The results of the simulations were compared with experimental results for the MMC in terms of macroscopic tensile stress–strain curves and conclusions were drawn.