Role of Carbon Vacancies on Mechanical Properties of Transition-Metal Carbide Thin Films
Abstract
Refractory transition-metal carbides, for example, compounds made of zirconium or tantalumand carbon, are extremely hard materials with some of highest melting points among all solids.Owing to their high mechanical strength even at elevated temperatures and excellent resistanceto wear, ablation, and corrosion, they are particularly attractive for applications in cutting tools,hard protective coatings, and as structural components in spacecrafts, rockets, and hypersonicjets. Often, their operation life-time and performance are limited because they are not ductile, i.e.they break or fracture instead of bending. Enhancing ductility will not only improve theirthermomechanical stability and performance in high-temperature structural applications butcould also open up potentially new low-temperature structural applications.This project aims to develop basic understanding of the role of carbide composition, crystal size,and crystal orientation on its mechanical properties. And use the knowledge gained through thesestudies to design thin layers of transition-metal carbides that are not only hard but also ductile.The underlying hypothesis is that, at small length scales, as in thin films, mechanical behavior ofcarbides can be controllably tuned by varying its composition, crystal size, and crystalorientation. To validate this hypothesis and to achieve the goal, a synergistic combination ofmaterials synthesis and their mechanical properties determined as a function of composition, filmthickness, and orientation using in situ microscopy based nanomechanical tests.Potential Impact and Benefit to the AFOSR: The proposed research will provideunprecedented insights into the role of composition, crystal size, and orientation on mechanicalbehavior of transition-metal carbides. Any improvements in their mechanical properties willsignificantly enhance the capabilities of our air force and space technologies.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 09, 2018
- Source ID
- FA95501810050
Entities
People
- Suneel Kodambaka
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of California, Los Angeles