Spongy metal sounds like a bit of an oxymoron, but it’s actually a real material that is capable of absorbing large impacts without damage. Metal foams have been around for some time, but new research by Dr. Afsaneh Rabiei of North Carolina State University, has revealed the strongest metal foam ever. It can compress up to 80% of its original size under loading and still retain its original shape. The applications for this type of material are too numerous to fathom, but one of the most anticipated uses for the spongy metal is in automobiles to lessen the impact of crashes and protect the driver and passengers.
Inventor Realizes Dream to Create Stronger Metal Foam
New material absorbs seven to eight times the energy absorbed by similar foams
Mechanical and aerospace engineering professor Afsaneh Rabiei set out to make a material as light as aluminum and stronger than stainless steel.
Her goal was to create something that could be used in products that would save lives, save energy and eventually save money, all at the same time.
While there are other metal foams in the market, Rabiei's is unique because she is using uniform hollow metal spheres, combined with a metal matrix. That helps the foam absorb energy much better than similar materials that have uneven cell structures or lack a metallic matrix. The foam she has created absorbs seven to eight times the energy absorbed by other metal foams made from similar materials.
Rabiei's foams can be made from stainless steel and various other metals. For biomedical applications, such as hip and knee implants, her metal foam can be created from titanium or cobalt chromium.
"So, if you put it in the body, the body will like it much better than a solid, heavy material because it is light and its mechanical properties are matching with that of bone," explains Rabiei, who also teaches biomedical engineering.