Keblinski, assistant professor of materials science and engineering at Rensselaer Polytechnic Institute, is the third Rensselaer faculty member this year and the 15th in the last three years to be recognized with a CAREER Award. He joined the Rensselaer faculty in 1999.
Keblinski is studying the role of interfaces on mechanical properties of polycrystals, such as diamond thin films grown by chemical deposition. His research in modeling the atomic bonding and the mechanical properties of polycrystalline diamonds will lead to better design of nanoscale materials that are stronger and less brittle.
While gem diamonds are single-crystal, diamond thin films grown by chemical deposition methods are polycrystal, which means they consist of many small crystalline diamond grains separated by interfaces, or edges, says Keblinski, a research leader of Rensselaer's nanotechnology modeling team. The strength of bonds between atoms at these interfaces is generally weaker than in perfect diamond crystals, which causes the material to be more brittle.
The role of interfaces becomes more significant at the nanoscale level because smaller crystals mean more interfaces, which could lead to even weaker material. Remarkably, experiments demonstrated that the strength of nanocrystalline diamond is essentially the same as that of gem diamond, which Keblinski explained with his modeling. Brittle materials fail because cracks grow and spread in a specific direction. But a crack that forms in one crystal could be stopped by an interface with enough strength and a different orientation of the crystal on the other side of the interface.
"Understanding the role of interfaces on mechanical properties, such as hardness and durability, is essential to designing materials," said Keblinski. "Because polycrystals are far more common in nature than single crystals, the knowledge derived from our studies of polycrystalline diamond can apply to other brittle materials such as ceramics." Ceramics are necessary for hard coatings or thermal protection barriers in turbines, for example.
Rensselaer Polytechnic Institute, founded in 1824, is the nation's oldest technological university. The school offers degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research and teaching. The Institute is especially well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.