U.S. Army adapts military-grade steel alloy for 3D printing ultra-strong parts

Researchers from the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory have adapted a specialized steel alloy for Powder Bed Fusion 3D printing. The new material, along with specific process parameters, can produce parts that are roughly 50% stronger than commercially available materials.

Within a military context, additive manufacturing has the potential to radically change logistics, offering a way to produce replacement parts and products on the fly. Though the technology is already being used in the field, its applications are still limited. The ability to produce ultra-strong metal components from the military-grade steel, however, could be a game changer.

“You can really reduce your logistics footprint,” said Dr. Brandon McWilliams, a team lead in the lab’s manufacturing science and technology branch. “Instead of worrying about carrying a whole truckload, or convoys loads of spares, as long as you have raw materials and a printer, you can potentially make anything you need.”

The material in question is AF96, a steel alloy originally developed by the U.S. Air Force for bunker-busting bomb applications. Researchers from the army laboratory adapted the material, which boasts high strength and hardness, into powder form so it can be used with Powder Bed Fusion technology. The researchers have successfully 3D printed complex components using the steel powder that would have been impossible to produce using more traditional manufacturing processes.

“The nice thing about that for the Army is that it has wide ranging applications,” McWilliams added. “We have interest from the ground combat vehicle community, so [AF96] could be used for replacement parts. A lot of our parts in ground vehicles now are steel. So this could be dropped in as a replacement not having to worry about material properties because you know it’s going to be better.”

“This material that we’ve just printed and developed processing perimeters for is probably about 50 percent stronger than anything commercially available,” McWilliams emphasized, adding that the challenge now is to certify the material for military applications.

“We’ve printed some empeller fans for the M1 Abrams [Main Battle Tank] turbine engine and we can deliver that part—they can use it, and it works,” he said. “But it’s not a qualified part. In terms of a battlefield scenario, that may be good enough to be able to get your tank running again for hours or days if that’s important to the mission, but on the other hand, we still need to be able to answer, does this perform as good as the OEM  part? Does this perform better?”

With that in mind, the army researchers are pursuing two strategies: one for battlefield sustainment, involving the production of replacement parts on demand; and one for futures systems. In the latter strategy, the researchers are working with OEMs and industry partners to see how additive manufacturing can be adopted and certified more broadly across the military.

Presently, the lab is working with its various industry and academic partners to model new alloy designs and perform computational thermodynamics. Ultimately, the aim is to deploy new, better performing alloys to soldiers in the field for 3D printing.

McWilliams concluded: “We’ve developed a road map and that’s an integrated plan that’s now focused on supporting our modernization priorities, but we’re also tied closely to the ground combat vehicle community.”