Size Effect on Functionally Graded Material Fabrication by Sedimentation

Abstract

A simple, economic, and scalable material manufacturing method of sedimentation has been used to fabricate functionally graded materials for solar roofing panels. This paper investigates the size effect of aluminum powder on the material gradation in the depth direction when only aluminum powder or the mixture of aluminum and high-density polyethylene (HDPE) powder is uniformly dispersed in ethanol and then subjected to sedimentation for a certain period, respectively. A Stokes’ law–based model is developed to simulate the sedimentation process, in which the concentration of aluminum and HDPE particles temporally and spatially changes in the depth direction due to the nonuniform motion of particles. The concentration variation further changes the effective viscosity of the suspension, and thus affects the drag force of particles. The numerical simulation demonstrates the effect of manufacturing parameters for sedimentation and predicts the graded microstructure of deposition in the depth direction. The present modeling and testing method provides a very useful tool for the material design and optimization of the solar roofing materials.