ADVANCED MATERIALS & PROCESSES | OCTOBER 2023 25 There’s a lot of buzz about a revolutionary new material at NASA’s Glenn Research Center that you both invented called GRX-810. What makes it so remarkable? Smith: Right now there’s a limit to the type of high-temperature properties you can obtain with 3D-printable conventional superalloys. Yet 3D printing is exploding in terms of applications in the space industry and even aeronautics. And so there was a demand for components that can be 3D printed and also have decent high-temperature properties. Comparing GRX-810 to the more conventional alloys that are being 3D printed, our alloy can withstand temperatures of 2000°F or 1100°C. A 3D printed component of Inconel 718 could last for 10 to 20 hours at 2000°F before rupturing; GRX-810 is somewhere between 2000 to 6000 hours. Our hope is that this is an alloy that can be used in the intermediate temperature range between superalloys and refractory alloys where there isn’t really a good material that you can use. It sounds like there was a particular problem you were aiming to solve. Smith: The problem came out of discussions with combustion designers here at NASA Glenn. They were 3D printing combustor domes, or injectors, out of cobalt chrome, which is an off-the-shelf high-temperature alloy that you can 3D print. But when they were tested, the components would fail catastrophically. They came to us and asked if there was an off-the-shelf printable alloy that won’t cause these premature failures during testing. We initially said that we don’t think so, because they wanted to operate at temperatures of 2000°F and higher. This kicked off the alloy-development program. We were trying to make an alloy that can be 3D printed and operate at the desired temperatures. You used computer modeling in your invention process. Was that a new aspect of your alloy development program? Smith: When we started out, there wasn’t too much modeling. A little bit here and there just to get a sense of broad alloy compositions and the type of structures you might get. We were getting nowhere fast. Then the pandemic forced us to go home. That’s where Chris enters the picture. Kantzos: We were able to use commercially available software to try and guess what type of structure the alloy was. You can plug in different elements and it will guess which phases form. It will estimate the freezing and the melting point. It will also show you where all the different elements are going. When we add carbon, we can learn where’s it going in the alloy and which element it is joining up with. Using that, we were able to iterate much more quickly and change different compositions. We came up with a composition that balanced a number of factors. And that was our jump into the GRX-810, which was an alloy that we thought could be printable, have high strength, oxidation resistance, and include the nano oxides. We added some refractory elements for increased performance. We added some elements for oxidation improvements. We were able to balance all of that in the modeling. In a way, was the pandemic a catalyst or accelerator to your process? Smith: As frustrating as that time was, yes, I give some credit to the situation in helping set this up for us. It helped us come up with a more creative solution. It led us to look for different tools. Kantzos: Tim and I are experimentalists at heart. Going home and forcing us to think more carefully about what we were doing instead of just jumping into it allowed us to come up with a composition that was much better in TECHNICAL SPOTLIGHT NASA’S NEW SUPERALLOY FOR EXTREME ENVIRONMENTS Hear from the co-inventors of NASA’s Alloy GRX-810, Tim Smith and Christopher Kantzos, about its exceptional high strength and durability for aerospace and other extreme conditions. 3D-printed combustor.
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