Composite metal foam can stop bullets and shield from radiation

April 13, 2016

April 13, 2016

The Advanced Materials Research Lab (AMRL) at North Carolina State University, USA, is reported to be developing a new class of metallic foam that combines the benefits of metal matrix composites with metallic foams. The composite metal foam (CMF) could have numerous applications and has recently been shown to stop armour-piercing bullets, as well as being able to shield radiation and offer extremely good thermal insulation.


The research has focused on developing the technology to process composite metal foams through both Powder Metallurgy and casting techniques. The CMF has up to eight times higher energy absorption compared to any other metal foam made from similar materials and its energy absorption is almost two orders of magnitude higher under loading compared to the original bulk materials.

Afsaneh Rabiei, Professor of Mechanical and Aerospace Engineering at NC State, has worked on developing CMFs and investigating their unusual properties. With support from the US Department of Energy’s Office of Nuclear Energy, Rabiei and her team showed that CMFs are very effective at shielding X-rays, gamma rays and neutron radiation. Rabiei has also published work demonstrating that these metal foams handle fire and heat twice as well as the plain metals they are made of.

Other potential applications of CMFs is in blast and ballistic armour. The results of Rabiei’s experiments have shown that CMFs were able to absorb the major portion of the total kinetic energy of projectiles effectively, in addition to stopping both types of type III and type IV (armour piercing) projectiles. Further studies on the capability of CMFs to protect against larger threats and blast are still ongoing.

“We could stop the bullet at a total thickness of less than an inch, while the indentation on the back was less than 8 millimetres,” stated Rabiei. “To put that in context, the NIJ [National Institute of Justice] standard allows up to 44 mm indentation in the back of an armour.”

The researchers have also subjected the material to high speed impact testing for automotive and train applications. These tests showed very high energy-absorption capabilities at a variety of impact speeds from quasi-static up to 100 meters per second. This indicates the potential for utilising CMFs in crash energy management systems in trains, cars, buses.

April 13, 2016

In the latest issue of PM Review…

Download PDF

Extensive Powder Metallurgy industry news coverage, and the following exclusive deep-dive articles and reports:

  • From powder modification to rejuvenation: Fluidised Bed Reactors in metal powder production and Additive Manufacturing
  • Retech: Enabling the atomisation of reactive and refractory alloys at substantially higher levels of productivity and lower cost
  • Sustainability in Powder Metallurgy: Highlights from the 41st Hagen Symposium
  • Innovations from Japan’s Powder Metallurgy industry: award winners highlight novel automotive and healthcare applications

The latest news from the world of metal powders, delivered to your inbox

Don't miss any new issue of PM Review, and get the latest industry news. Sign up to our weekly newsletter.

Sign up

Join our community

Discover our magazine archive…

The free-to-access PM Review magazine archive offers unparalleled insight into the world of Powder Metallurgy from a commercial and technological perspective through:

  • Reports on visits to leading PM part manufacturers, metal powder manufacturers and industry suppliers
  • Articles on technology and application trends
  • Information on materials developments
  • Reviews of key technical presentations from the international conference circuit
  • International industry news

All past issues are available to download as free PDFs or view in your browser.


Browse the archive


Looking for PM production equipment, metal powders, R&D support and more?

Discover suppliers of these and more in our
advertisers’ index and buyer’s guide, available in the back of PM Review magazine.

  • Powders & materials
  • Powder process, classification & analysis
  • PM products
  • Atomisers & powder production technology
  • Compaction presses, tooling & ancillaries
  • Sintering equipment & ancillaries
  • Post-processing
  • Consulting & toll sintering
View online
Share via
Copy link