Scientists are racing to create materials tough enough for hypersonic flight

Penn State University has teamed up with UK-based Battalion Advanced Technology Ltd on two major research projects worth up to £4.5 million, with the aim of developing advanced semiconductors and high-temperature materials for next-generation technology and national security.

The three-year collaboration will be led by researchers at Penn State's Materials Research Institute (MRI).

The projects are tackling two very different challenges.

One is focused on making advanced semiconductors work with materials that can withstand intense heat while helping to move heat away from sensitive components.

The other is looking at new metal alloys capable of maintaining their strength and stability in extreme temperatures — including the punishing conditions experienced during hypersonic flight.

Battalion Advanced Technology, a UK company specialising in next-generation materials for dual-use applications, will provide up to £750,000 per year for each project.

The agreements came into effect on July 16 and will run for three years.

"Penn State Materials brings together expertise in semiconductor science, computation, manufacturing and characterization," said Joshua A. Robinson, director of the MRI and professor of materials science and engineering. "This collaboration allows us to apply that breadth to two complex materials challenges with direct implications for U.S. technological leadership and national security."

U.S. Senator Dave McCormick, commented: "Pennsylvania has the talent, research institutions, and innovative spirit to help America lead in the technologies that will define our economic and national security.

“This research collaboration, backed by up to $6 million from Battalion Advanced Technology, will help Penn State advance critical work in semiconductors, aerospace, defense, and other strategic industries while strengthening Pennsylvania's role as a hub for American innovation."

Building better semiconductors

The first project is being led by Joan Redwing, distinguished professor of materials science and engineering and of electrical engineering.

Her team is investigating ways to combine gallium nitride and other advanced semiconductors with materials that offer better thermal and electrical performance.

Gallium nitride can operate at higher voltages, temperatures and power densities than many conventional semiconductor materials, making it an exciting option for future electronics, communications and sensing technology.

But there's a problem.

The materials that semiconductors are grown on can limit their performance, particularly at the point where two different materials meet.

Researchers will investigate whether incredibly thin layers of material could help solve that problem.

The team plans to explore atomically thin interlayers that could help gallium nitride integrate more effectively with materials such as diamond and aluminium nitride.

The goal is to reduce defects, relieve stress between materials and improve the way heat is transferred.

"By using atomically thin two dimensional materials as interlayers, we aim to minimize crystalline defects and interfacial thermal resistance while enabling wide-bandgap semiconductor growth on high thermal conductivity substrates that have traditionally been incompatible with direct deposition," Redwing said.

The semiconductor project also includes co-principal investigators Joshua A. Robinson, Adrianus van Duin and Chen Chen.

Metals built to take the heat

The second project is being led by Douglas Wolfe, associate vice president for research and professor of materials science and engineering.

His team is turning its attention to refractory metal alloys — specialist metals capable of maintaining their strength and stability at extremely high temperatures.

Materials such as tungsten, molybdenum and niobium already have impressive heat-resistant properties, but oxidation and material loss can limit their use.

The researchers want to develop new alloy compositions and structures that can maintain their mechanical performance while forming more stable protective surfaces when exposed to extreme heat.

They will also investigate functionally graded materials, where the composition or structure changes across a component, as well as protective systems designed to improve resistance to oxidation and increase durability.

The research could eventually have applications across defence, hypersonics, nuclear technology, space exploration and other extreme environments.

"By integrating computational prediction, next generation manufacturing and rigorous validation, we can accelerate the development of refractory alloys that enable breakthroughs in defense applications, hyper sonics, nuclear systems, space exploration and other extreme environmental applications," Wolfe said.

Long-Qing Chen and Bed Poudel are co-principal investigators on the refractory alloy project.

R. Michael Jones, Director of Battalion, commented: "We are very pleased to be supporting the development of leading innovations with essential dual uses for national security and economic technologies.

“We are able to work on highly sophisticated solutions immediately through our partnership with Penn State."

The partnership brings together university research and industry expertise in a bid to solve some of the biggest materials challenges facing future high-performance technology.

If successful, the work could help pave the way for electronics and components capable of operating in environments where conventional materials simply cannot cope.