Composite metal foams (CMFs) are tough enough to turn an armor-piercing bullet into dust on impact. Given that these foams are also lighter than metal plating, the material has obvious implications for creating new types of body and vehicle armor – and that’s just the beginning of its potential uses.

Afsaneh Rabiei (see bio below), a professor of mechanical and aerospace engineering at NC State, has spent years developing CMFs and investigating their unusual properties. The video seen here shows a composite armor made out of her composite metal foams. The bullet in the video is a 7.62 x 63 millimeter M2 armor piercing projectile, which was fired according to the standard testing procedures established by the National Institute of Justice (NIJ). And the results were dramatic.

(The video can also be found at:

https://www.youtube.com/watch?v=lWmFu-_54fI ).

“We could stop the bullet at a total thickness of less than an inch, while the indentation on the back was less than 8 millimeters,” Rabiei says. “To put that in context, the NIJ standard allows up to 44 millimeters indentation in the back of an armor.” The results of that study were published in 2015.

But there are many applications that require a material to be more than just incredibly light and strong. For example, applications from space exploration to shipping nuclear waste require a material to be not only light and strong, but also capable of withstanding extremely high temperatures and blocking radiation.

Last year, with support from the Department of Energy’s Office of Nuclear Energy, Rabiei showed that CMFs are very effective at shielding X-rays, gamma rays and neutron radiation. And earlier this year, Rabiei published work demonstrating that these metal foams handle fire and heat twice as well as the plain metals they are made of.

Now that these CMFs are becoming well understood, there could be a wide array of technologies that make use of this light, tough material. Armor, if you’ll forgive the pun, barely scratches the surface.

Bio: Afsaneh Rabiei

​Dr. Rabiei enjoys solving advanced materials problems aimed at improving our health, safety and environment. Her goal is to create new materials along with improving the properties and performance of existing materials by altering their manufacturing techniques and by studying their micro-structural and mechanical characterization and their failure analysis. Dr. Rabiei is currently working in the areas of 1) coatings, 2) metal foams, and 3) cellular materials. The coatings work is being applied to biomedical implants, thermal barrier coatings, and refractory materials. Her research includes the deposition of such coatings as well as their mechanical and micro-structural evaluation and failure analysis. Her research in cellular structures focuses on metal foams for which improved energy absorption and radiation shielding are being realized. Her study of ultra-light materials addresses advantages that can be gained not only in biomedical and dental implants and safety devices for protection against various threats such as accidents, explosions or earthquakes, but also for energy conservation and alternative-energy applications.

Dr. Rabiei teaches Advanced Materials. In this course, Dr. Rabiei exposes students to newer classes of materials like metal foams, coatings, composites and thin films. She also surveys the current state-of-the-art in advanced materials and presents a comparison of our in-house capabilities with the state-of-the-art. At the undergraduate level, she teaches Statics (MAE-206 course link), Solid Mechanics and Strength of Mechanical Components. These are classical courses but she likes enriching these courses with discussions on environmental and physical properties exhibited by a wide variety of materials and real life applications. She also presents Undergraduate Research through MAE496 and MAE586. In this course an undergraduate student will be teamed up with a graduate student and will be assigned to work on a research project. Dr. Rabiei is a unique faculty advisor. Her students often work with professionals outside of MAE, on and off campus and quite often with international groups. Her students tend to be motivated, have good reading and writing skills, and enjoy scientific exploration. Much of her work leads to new inventions. She is fond of pointing out that her students work in an environment of creation.

Outside of work, Dr. Rabiei enjoys her time with family and students.

(C) NCSU News Service