US Army engineers explore improved armour-plate alloys to boost soldier safety

9 December 2013 (Last Updated December 9th, 2013 18:30)

Engineers at the US Army Research Laboratory (ARL) are currently carrying out research on improved alloys for armour-plates, which would be used on the military's ground systems to boost soldier safety.

Armor plates

Engineers at the US Army Research Laboratory (ARL) are currently carrying out research on improved alloys for armour-plates, which would be used on the military's ground systems to boost soldier safety.

Aimed at defining whether a new or improved aluminium alloy's properties go beyond the existing material options, the programme would also assist determining whether the material being procured complies with the essential stringent requirements.

The ARL-led effort has sought the Office of the Secretary of Defense Comparative Technology Office to fund for materials and equipment including bullets, X-rays, guns and powder.

Research also involves carrying out a series of standardised tests on a new alloy selected for US ground forces, to certify its performance in the ballistic protection level, corrosion resistance and weldability.

ARL Corrosion and Surface Science team leader Brian Placzankis said that adhering to the requirements for all three aspects is critical to soldier safety because a failure could be fatal.

"The ARL Weapons and Materials Research Directorate is trying to down-select viable plate alloys for the army to use," Placzankis said. "We separate the contenders from the pretenders."

During the research, engineers noticed that Aluminum Alloy 7017 exhibited a cutback in spallation when compared with the AA7039.

Armor Mechanisms Branch general engineer Denver Gallardy said that when a projectile strikes the front of the plate, it sends a compressive wave through it.

"The compressive wave hits the back surface of the plate and it reflects as a tensile wave."

"The compressive wave hits the back surface of the plate and it reflects as a tensile wave," Gallardy said.

"If the tensile stresses developed by the wave are higher than the tensile strength of the material, you get a large piece of a material, bigger than the caliber of the projectile, that breaks off.

"Even though the projectile stopped in the plate, a piece of material with residual energy capable of causing damage flies off the back."

The research will also allow replacing or improving old alloys that are used in shields protecting the legacy vehicles, which would offer better protection and performance economically.

The ARL-validated aluminum alloys can be incorporated on all types of vehicles, including mine-resistant ambush-protected vehicles, Humvees and lightweight armoured vehicles such as personnel carriers and the Bradley Fighting Vehicle.


Image: Army engineers are working on improving alloys for armour-plate applications and boost Soldier safety. Photo: courtesy of Conrad Johnson, RDECOM.

Defence Technology