Aluminum–ceramic cenospheres syntactic foams produced by powder metallurgy route

• Published in: Materials & design 2015-11, Vol.85, p.444-454
• Main Authors: Vogiatzis, C.A., Tsouknidas, A., Kountouras, D.T., Skolianos, S.
• Format: Article
• Language: English
• Subjects: Aluminum; Cenospheres; Compressive strength; Deformation mechanisms; Density; Fracture; Mechanical properties; Metal matrix syntactic foams; Porosity; Powder metallurgy; Syntactic foams
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2015.06.154

Aluminum–cenospheres syntactic foams of different compositions and varying relative densities were fabricated by powder metallurgy using a low compaction load (ranging from 200MPa to 300MPa). The produced composites were examined in terms of density, porosity, macro- and micro-structural characteristics. Mechanical properties of the sintered samples, like compressive strength and deformation mechanisms, quasi-elastic modulus and absorbed energy were also investigated. A novel theoretical model reflecting the compressive strength of aluminum–cenospheres syntactic foams was developed with respect to the production conditions (compact pressure) of the “green body”. Finally, the influence of the powder metallurgy route on the deformation mechanisms and fracture strength of the metal matrix syntactic foams was elicited, providing refined insight to optimum production parameters. The yielded results stipulate that characteristic properties like porosity inhomogeneity or insufficient bonding between matrix particles have a direct impact on the final properties of metal syntactic foams. As the compact pressure and the volume fraction of the cenospheres increases, composites exhibit a mechanical response typical of metal matrix syntactic foams. [Display omitted] •Powder metallurgy route was employed to produce cenospheres-Al syntactic foams.•The effect of compaction pressure on the density and porosity was investigated.•The deformation mechanisms of various composites were examined and evaluated.•A model was developed to predict the effect of the production conditions on their mechanical properties.