Structural ceramic coatings in composite microtruss cellular materials

• Published in: Acta materialia Vol. 59; no. 15; pp. 6145 - 6154
• Main Authors: Bele, E., Bouwhuis, B.A., Codd, C., Hibbard, G.D.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-09-2011; Elsevier
• Subjects: Aluminum alloy; Aluminum base alloys; Aluminum oxide; Anodic coatings; Anodization; Applied sciences; Buckling; Cellular materials; Coatings; Composite materials; Compression test; Compressive strength; Exact sciences and technology; Failure mechanisms; Fracture mechanics; Mathematical analysis; Metals. Metallurgy; Nonmetallic coatings; Other surface treatments; Production techniques; Struts; Surface treatment; Cellular materials; Compression test; Buckling; Anodization; Aluminum alloy; Anodizing; Cellular material; Non metal coating; Ceramic materials; Composite material; Surface treatment
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2011.06.027

The compressive strength increase per unit sleeve thickness of Al cores reinforced with Al
2O
3 sleeves is lower than the corresponding strength increase when the same cores are reinforced with nanocrystalline Ni (n-Ni) sleeves (left). However, because anodizing is a transformative surface treatment, the Al
2O
3 coating was able to achieve this performance increase with little overall weight penalty (right).
[Display omitted]
► A new type of metal/ceramic microtruss cellular composite has been created. ► Reinforcing sleeves of Al
2O
3 were deposited on low density Al microtruss cores. ► Significant compressive strength increases were seen at virtually no weight penalty. ► Failure mechanisms were studied by electron microscopy and finite element analysis. ► Buckling, sleeve wrinkling, and coating fracture dictated the compressive strength.
In the present study, anodizing was used to produce Al
2O
3 coatings in a conventional 3003 aluminum alloy microtruss core; a 38.5
μm 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.