Ultra strong metal alloy foam floats on water
Lightweight syntactic foam composite is less dense than water but withstands more than 25,000 PSI.
With a density of 0.92 grams per cubic centimeter, the syntactic foam starts with a matrix made of a magnesium alloy, which is then turned into foam by adding strong, lightweight silicon carbide hollow spheres developed and manufactured by DST. The hollow particles also offer impact protection to the syntactic foam because each shell acts like an energy absorber during its fracture.
According to the researchers, the composite can be customized for density and other properties by adding more or fewer shells into the metal matrix to fit the requirements of the application. It can also be used with other magnesium alloys that are non-flammable.
“This new development of very light metal matrix composites can swing the pendulum back in favor of metallic materials,” forecasted Nikhil Gupta, an NYU School of Engineering professor in the Department of Mechanical and Aerospace Engineering and the study’s co-author. “The ability of metals to withstand higher temperatures can be a huge advantage for these composites in engine and exhaust components, quite apart from structural parts.”
For example, Gupta says the new composite has potential applications in boat flooring, automobile parts and buoyancy modules as well as vehicle armor. A boat made of such lightweight composites, for example, wouldn’t sink despite damage to its structure. The new material could also improve automotive fuel economy due to its combination of light weight and heat resistance.
The NYU researchers say the composite is close to maturation and could be put into prototypes for testing within three years. The research, recently published in the International Journal of Impact Engineering, was conducted in collaboration with the U.S. Army Research Laboratory.