Effective thermo-mechanical properties of aluminum–alumina composites using numerical approach

Abstract

This study examines the effect of microstructural characteristics on the effective thermo-mechanical properties, i.e., elastic moduli, Poisson’s effect, and coefficient of thermal expansion (CTE), of ceramic particle-reinforced metal–matrix composites. Two-dimensional (2D) micro-structures for composites with 10% and 20% alumina volume contents dispersed in aluminum matrix are constructed from the micrograph images of the composite samples taken at various locations. A representative area element approximately of size 50μm×50μm is chosen to represent the microstructure of the composite. For each of the selected square regions, ceramic content and porosity are first determined in order to examine the validity of the represented microstructure. These microstructures are implemented in finite element (FE) in order to numerically characterize the effective thermo-mechanical properties of the composites. The alumina constituent is assumed to behave as linearly elastic solid, while the aluminum constituent is modeled as an elastic–plastic solid with material parameters varying with temperatures. The effect of loading directions, porosity, properties of the constituents, particle sizes, and thermal (residual) stresses developed during cooling from the sintering temperature to room temperature, on the overall thermo-mechanical properties of the composites are further discussed.