How additive manufacturing makes "impossible" materials possible

NASA made aviation history in 2014 with the first and second successful flights of a scramjet-powered airplane at hypersonic speeds—Mach 5, or five times the speed of sound. NASA

I spoke with an AM entrepreneur a few days ago. I’ll call him Bob. The guy was not only a brainiac but fun to talk to. Someone who laughed a great deal and clearly enjoyed what he was doing.

Bob's work? Constructing impossible parts from equally impossible materials. A little research revealed that he's not the only one traveling the "impossible" road. And because of him and his traveling companions, AM, and impossible materials, the world will be a far different place in a decade or two.

The materials are called refractory metals. Elemental stuff like tungsten, molybdenum, and niobium. Metals so strong, tough, and heat-resistant that they’re damned near impossible to machine. Printing them, however, is seemingly no big deal.

I know from first-hand experience how crappy these materials are to cut, because back in the day every bit of nickel-based alloy, hardened steel, or refractory metal that came in the door was immediately wheeled over to my machine. (I don't think my boss liked me.)

One of these was tantalum. It has a melting point of 3,017°C (5,463°F), more than twice that of Inconel X750, a favorite of the gas turbine engine industry. I didn't know that at the time. What I did know is that we lost our butt on the job, because I went through half a dozen inserts on every part.

Bob, on the other hand, apparently can 3D-print turbine parts out of such refractory materials with relative ease. In fact, he showed me some of them. They’re beautiful.

Why is that important? I’m no gas turbine engineer, but my understanding is that the hotter you can run one, the more efficient it becomes. This is why manufacturers spend so much time and money cutting cooling channels in turbine blades. It allows them to spin faster and reach higher temperatures without melting. (Bad things happen when turbine blades melt.) But with AM, making all those cooling channels are a piece of cake, as are geometries that people like Bob have yet to dream up.

Bob has a contract with NASA. They’re working on the next scramjet. If successful, it promises speeds of Mach 15, or 11,509 mph. Imagine flying from New York to Los Angeles in 12 minutes. There’d hardly be time for a beer, let alone a sandwich.

More importantly, it means that achieving Earth orbit would become a whole lot cheaper, bringing low-cost space travel much closer to reality. And that's just one of the many applications for refractory metals.

Like I said, thanks to 3D printing the world might be a far different place soon.