Research of materials for use in extreme environments

  • Published
  • By Erin Crawley
  • Air Force Office of Scientific Research Public Affairs
ARLINGTON, Va. (AFNEWS) --  Leading edge scientific discoveries and breakthroughs funded by the Air Force Office of Scientific Research here could pave the way for new performance capabilities of materials used in extreme environments.

Among these latest developments, recently presented at an AFOSR ceramics program review, is the discovery of a new, previously unknown compound that could significantly impact the future of hypersonics.

Dr. Joan Fuller, AFOSR's ceramics and non-metallic materials program manager, spearheaded the event at the National Science Foundation here. World-class materials researchers presented their most recent discoveries and fundamental advancements funded by AFOSR.

Dr. Fuller stressed the importance of basic research in the area of ceramics and non-metallic materials.

"There are many application areas where a deeper understanding of the fundamental science of structural ceramics could enable revolutionary advancements," Dr. Fuller said. "In particular, the Air Force requires strong and light-weight materials that can operate in extreme thermal and chemical environments."

As examples, she mentioned the leading-edge of a hypersonic plane, the combustor of a turbine engine, or the optical path of a direct energy weapon.

"In addition to the mechanical requirements of the materials, the components will likely all involve complicated shapes that will require the development of new processing and manufacturing techniques," Dr. Fuller said. "It is highly probable that future Air Force mission requirements will simultaneously impose extreme thermal and chemical operating environments. Therefore, future materials systems must be discovered and developed for these unique operating environments."

By supporting scientists like Dr. Inna Talmy, Dr. Fuller can come closer to meeting these challenges and create a new pathway for the future of ceramics.

Dr. Talmy manages the ceramics laboratory at the Naval Surface Warfare Center Carderock Division in Bethesda, Md. She's an internationally recognized expert in ultra-high temperature ceramics and radome materials. In collaboration with AFOSR, her research group is exploring a class of materials called cermets. Cermets are ceramic-metal composites capable of compensating for the intrinsic brittleness of ceramics at room temperature while maintaining the high temperature properties inherent in ceramic materials.

Dr. Talmy and her colleague, Dr. Jim Zaykoski, recently discovered a new compound. The two researchers discovered it while attempting to prepare a cermet containing tantalum as the metal component and zirconium diboride as the ceramic component. Both materials have very high melting points.

"We anticipated the two elements might not react because they were found to be chemically incompatible," Dr. Talmy said. "However, they did react and a new compound formed. There are no data in the literature on this compound. So, we actually discovered the new material. Together with Dr. Winnie Wong-Ng at the National Institute of Standards and Technology, we have identified the structure of this new compound."

The new compound has a crystal structure with elongated interlocked grains, which results in increased strength. The strength of the new ceramics is significantly higher than that of zirconium diboride, a material that already has great potential for applications at ultra-high temperatures and has excellent resistance to oxidation and corrosion.

Other scientists within Dr. Fuller's portfolio have also made some recent advances in the development of a new process called melt texturing, and important micro-structural observations in how materials interact with one another in the operating environment. 

Comment on this story (comments may be published on Air Force Link)

Click here to view the comments/letters page