The Mach-X engineering team at the University of Arizona is working to make hypersonic vehicles faster and more affordable. Now, they’ve received a $5 million grant from the U.S. Army to help in their work. The National Center for Defense Manufacturing and Machining (NCDMM) has charged the team with developing an efficient, cost-effective method for alloy manufacturing, using 3D printing and machine learning, to make critical, high-tolerance parts for aircraft that fly at least five times the speed of sound.

This is the second U.S. Army grant the Mach-X team has been awarded this year. In March, it received $3.1 million to develop refractory alloys for the project. That’s a total of $8.1 million in military funding this year alone to speed up hypersonics manufacturing. Plus, two years ago, the university’s Arizona Research Center for Hypersonics was awarded a $1.2 million grant from the Office of Naval Research’s Defense University Research Instrumentation Program to purchase equipment for hypersonic research.

“These very significant awards are further evidence that the University of Arizona is a leader in hypersonics research. The funding brings together academia, government and industry to expand research capacities while supporting national priorities in homeland security and technology,” said David W. Hahn, the Craig M. Berge Dean of the College of Engineering.

“We are pioneering metal 3D printing techniques, as well as new and innovative alloys that can support the next generation of affordable hypersonic platforms,” said Mach-X team leader Sammy Tin, the Patrick R. Taylor Endowed Department Leadership Chair of Materials Science and Engineering and the grant’s principal investigator.

Image: Nastco/Raytheon

As Tin explained, a “leading-edge structure or rocket nozzle structure” has to be able to survive under high stresses, and at temperatures above 1,000°C, for extended periods of time. So in developing their alloy manufacturing method, the team will need to determine the proper mix of metal materials, as well as create a strong 3D printed microstructure that’s able to handle the intensity of hypersonic flight. They are partnering with Raytheon, an RTX business, to use nickel alloys for the development of prototypes that can tolerate these stressful conditions.

The Mach-X team will refine their process using nonlinear acoustic detection, a sophisticated nondestructive process that tests the integrity of 3D printed parts using sound waves.They’re also turning to machine learning in order to create computer simulations of their print formations so they can catch any mistakes or defects before anything gets too far.

“We can assess the quality of the part as we’re building it and make on-the-spot decisions if we need to go back and update the process,” explained Krishna Muralidharan, a member of Mach-X and a professor in the Materials Science and Engineering Department.

“We will train the algorithm on the simpler parts and use it to interpret the acoustic responses from the testing process. That will tell us with a high degree of confidence if there are defects and which structures are working.”

The Mach-X research team. Front row, from left: Krishna Muralidharan, Kavan Hazeli, Andrew Wessman and Oana Cazacu. Back row, from left, Benoit Revil-Baudard and Sammy Tin. The team uses emerging technologies like machine learning to boost the production of ultrafast aircraft. Image: University of Arizona

Materials like refractory alloys, such as Niobium C103 and Niobium Super C103, and nickel-based superalloys are often used for hypersonic applications, though composites have also been explored. This project will certainly speed up the university’s discovery-to-deployment cycle for advanced materials.

Tin said, “We can develop the powder, customize the alloy compositions, print in 3D, evaluate the products non-destructively, and ultimately do very high temperature mechanical testing here.

“We will have unique, end-to-end capabilities on campus that very few universities or industrial companies have.”

With all the interest in hypersonics from a defense standpoint, including not only aircraft but also weapons, many government entities will likely be watching closely to see what the Mach-X team comes up with for the NCDMM project.

“This grant reflects how the University of Arizona’s well-regarded expertise in hypersonics and materials sciences can bolster the nation’s defense capabilities. Developing and fostering research partnerships of this kind helps the U of A shape the future and address pressing challenges, and we are excited to see what the Mach-X team designs,” said Tomás Díaz de la Rubia, University of Arizona Senior Vice President for Research and Partnerships.

In addition to Muralidharan and Tin, the Mach-X team includes materials science and engineering faculty members Oana Cazacu, Andrew Wessman, and Benoit Revil-Baudard, as well as Ron Liang, the Thomas R. Brown Endowed Chair in the Wyant College of Optical Sciences, Tribikram Kundu from the Department of Civil, Architectural Engineering and Mechanics, and Kavan Hazeli from the Department of Aerospace and Mechanical Engineering.