Effect of Cell Morphology and Heat Treatment on Compressive Properties of Aluminum Foams

Abstract

In this article, the compressive behavior and anisotropy of both open- and closed-cell aluminum foams under different heat treatments were examined. For the closed-cell A356/SiCp foam, due to the age-hardening effect, the yield strength of the heat-treated specimens was found to be more than 200% of that of the as-cast specimens. The yield strength of the foam in the transverse direction was however only slightly higher than that in the longitudinal direction, which may be related to the relatively spherical cell structure of the foam. For open-cell Al6061 foams, heat treatment results in a significant increase in yield strength and also changes the failure mode from ductile to brittle. The open-cell foam further demonstrates a strong anisotropy. The causes of such phenomena are discussed in the article.

Keywords:

• Metal foams
• Open cell
• Closed cell
• Cell morphology
• Compressive properties
• Deformation mechanisms
• Heat treatment
• Anisotropy

Acknowledgments

The work described in this article was supported by the Research Committee of The Hong Kong Polytechnic University (Project no. A-PC85). The authors want to thank Dr. M. C. Gui of Institute of Aeronautical Materials for the provision of the closed-cell aluminium foams.