Structural ceramic coatings in composite microtruss cellular materials

In the present study, anodizing was used to produce Al2O3 coatings in a conventional 3003 aluminum alloy microtruss core; a 38.5 mu m thick anodic coating provided a 143% increase in compressive strength. Finite-element analyses were used to illustrate the dependence of the compressive strength and failure mechanism on the thickness of the anodic coating. At low thicknesses the microtruss strength is dictated by global bucking of the internal struts. However, at higher thicknesses the compressive strength is controlled by coating fracture and local deformation in the hinge region of the struts. Regardless of the failure mechanism, the compressive strength of the composite microtruss increased with increasing anodic coating thickness, with very little corresponding weight penalty. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.