Al–Al2O3 syntactic foams – Part I: Effect of matrix strength and hollow sphere size on the quasi-static properties of Al-A206/Al2O3 syntactic foams

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 582; pp. 415 - 422
• Main Authors: Santa Maria, J.A., Schultz, B.F., Ferguson, J.B., Rohatgi, P.K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 10.10.2013; Elsevier
• Subjects: Aluminum alloys; Applied sciences; Casting; Cellular materials; Composites; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Elasticity, elastic constants; Exact sciences and technology; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical characterization; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Mechanical properties of solids; Metal matrix syntactic foam; Metals. Metallurgy; Physics; Porous materials; granular materials; Specific materials; Casting; Cellular materials; Aluminum alloys; Composites; Mechanical characterization; Metal matrix syntactic foam; Heat treatment; Spherical shape; Syntactic foam; Mechanical properties; Cellular material; Composite material; Fracture toughness; Thickness; Hollow sphere; Hollow shape; Metal foam; Yield strength; Microstructure
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2013.05.081

The microstructure and quasi-static compressive mechanical properties of Al-A206/Al2O3 hollow sphere syntactic foams were investigated for foams with three different hollow sphere size ranges (0.106–0.212mm, 0.212–0.425mm, 0.425–0.500mm) and three different conditions including As cast (F), T4 and T7. The peak strength, plateau strength and toughness of the foams were found to increase with increasing wall thickness to diameter (t/D) ratio. Since the t/D ratio was found to increase with decreasing sphere diameter, the foams produced with the smallest hollow spheres (0.106–0.212mm) showed superior performance for the peak strength (F: 226MPa, T4: 312MPa, T7: 342MPa), plateau strength (F: 190MPa, T4: 269MPa, T7: 269MPa), and toughness (F: 59J/cm3, T4: 78J/cm3, T7: 88J/cm3). These properties were also found to generally increase with increasing matrix yield strength. The 0.212–0.425mm T7 heat treated syntactic foams in this study exhibit the highest specific plateau strength (102MPa-cm3/g) and the second highest specific energy absorption (41J/g) of aluminum syntactic foams reported in literature for which comparable data is available.