Composite metal foam. Afsaneh Rabiei/North Carolina State University
A new innovative material called Composite Metal Foam (CMF) is finally ready for production after undergoing years of extensive testing.
This material is unlike anything created so far. Notably, CMF combines the strength of steel with the lightness of aluminum and is resistant to ballistic impacts, fire, and radiation.
Engineer Afsaneh Rabiei of North Carolina State University has been perfecting CMF for over a decade.
Advanced Materials Manufacturing (AMM) recently announced they are ready for full-scale production of this metal foam.
Following testing, CMF has proven effective in reducing weight, size, and carbon emissions while improving safety and performance in advanced engineering structures.
Incredibly strong with lightweight
This robust and lightweight material is composed of a network of hollow metal bubbles integrated into a matrix of steel, titanium, aluminum, or other alloys.
According to Rabiei, CMF stands out as the strongest metal foam, even though it’s not the first of its kind.
The evidence is compelling. In a 2019 study, researchers found that CMF vehicle armor provided equivalent protection against .50 caliber rounds (both ball and armor-piercing) compared to conventional steel armor.
The CMF layer absorbed 72-75% of the kinetic energy from ball rounds and 68-78% from armor-piercing rounds.
Crucially, the CMF armor achieved this protection at less than half the weight.
The major weight reduction offered by CMF armor means better vehicle performance and fuel economy.
“The CMF armor was less than half the weight of the rolled homogeneous steel armor needed to achieve the same level of protection,” Rabiei stated in the 2019 press release.
“In other words, we were able to achieve significant weight savings—which benefits vehicle performance and fuel efficiency—without sacrificing protection,” Rabiei added.
Excels at heat insulation
In the last few years, the metal foam material was subjected to rigorous testing to assess its performance against ballistics, blasts, vibrations, radiation, and fire.
CMF also excels at heat insulation. A 2016 study published in the International Journal of Thermal Sciences showed that CMF insulates against heat significantly better than solid metal.
Researchers exposed a solid stainless steel sheet and a CMF sample to a 1472°F (800°C) flame. The steel reached a certain temperature in four minutes, while the CMF took twice as long – eight minutes.
CMF’s superior heat insulation is due to the air pockets within its structure. As Rabiei explained, heat travels more slowly through the air than metal.
This property makes CMF suitable for protecting heat-sensitive materials, from hazardous chemicals to spacecraft.
CMF shows promise for spacecraft construction due to its radiation-shielding properties.
The material has been proven effective against X-rays and gamma rays – the dangerous radiation prevalent in space. It also shows potential for blocking neutron radiation, such as that emitted by nuclear reactors and explosions.
“In short, CMFs hold promise for a variety of applications: from space exploration to shipping nuclear waste, explosives and hazardous materials, to military and security applications and even cars, buses and trains,” Rabiei said in the earlier release.
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AMM announced that it is now accepting orders for custom CMF designs in various shapes, sizes, and materials.
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Mrigakshi Dixit Mrigakshi is a science journalist who enjoys writing about space exploration, biology, and technological innovations. Her work has been featured in well-known publications including Nature India, Supercluster, The Weather Channel and Astronomy magazine. If you have pitches in mind, please do not hesitate to email her.
