22 Apr 2022
Aluminium Foam: One Material, Innumerable Uses

Aluminium foam is a curious material developed using aluminium as the base metal. It is commonly made by injecting a gas or mixing a foaming agent into molten metal. Featuring a rigid network of interconnected aluminium ligaments that form cells with both open and closed pores depending on the production process, aluminium foam offers myriad advantages. It has the capacity to float in water, be flame-retardant, improve sound insulation and possesses excellent energy absorption. It is also very malleable and can be easily processed by drilling, sawing, and joined simply by adhesive or welding.

Aluminium foam’s versatile properties lend itself to a variety of cutting edge uses that can change the way we approach manufacturing and give familiar products a completely new lease of usefulness. For example, researchers have been able to develop a lightweight alternative to the heavy armour used by military vehicles, using aluminium panels merged with ceramic and steel. This material has proven strong enough to stop moderate to severe blast loads, similar to conventional armour but at only half its normal weight. This would, researchers say, enable the development of lighter, faster, and more efficient military vehicles without a need to compromise on the safety of soldiers.

In Europe, aluminium foam lies at the core of Proteus, a material which, according to its UK and Germany-based developers, is nearly impossible to cut or drill into. Made out of aluminium foam embedded with small ceramic spheres, it works by repelling the force applied by cutting tools and transmitting it back on them, effectively neutralising their damaging capability. Possible applications for this wonder material include tougher work boots for factory workers, stronger locks and safes, and sturdier aluminium frames for homes.

Scientists at North Carolina State University are also working on a novel application of aluminium foam: a replacement material for damaged bones. They are doing this with the help of CMF or Composite Metal Foam, which can made out of several metal alloys, including aluminium. The CMF material is up to 65% more porous than the bulk metal on which it is based, which can be further adjusted to match the bone porosity of patients based on their age or bone condition. This property can potentially help overcome common medical side-effects of body implants, such as bone rejection, while presenting a more resilient and comfortable alternative for patients.

Clearly, these emerging applications suggest that aluminium is a transformative material that transcends sectors, whose uses are limited only by the imagination of scientists and the limitations of existing technology. With time, we may yet uncover many more exciting purposes for the Metal of the Future!