An integrated approach to revolutionary aeropropulsion and power technologies
Sponsor: NASA URETI Grant
P.I.: M. Dunn Co-PI’s: M. Walter, S. Ghosh, M.J. Mills, J. Williams, G.S. Daehn
Keywords: Thermal Barrier Coatings, Instability Analysis
Abstract:
Improved methods for calculating component life rely on understanding the failure modes and their relationship to the component operating environment. Improved understanding of the role of ceramic inclusions as crack initiation sites in powder metallurgy Ni base disk alloys will remove a considerable penalty currently paid in the form of life margin debit. Improved tools for predicting failure modes and mechanisms of thermal barrier coatings (TBC) on Ni base monocrystal turbine airfoil castings will permit the eventual use of TBC coated airfoils for lifetimes that assume that the TBC is prime reliable and will not spall prior to the calculated life. Improved life methods will therefore provide: 1) performance benefits by eliminating unnecessary conservatism, and 2) economic benefits by allowing longer safe operating lifetimes of high cost, critical components. This task will focus on developing new methods and models to improve on current “best practices” relative to life prediction in critical parts.
Thermal barrier coatings (TBCs), which allow higher gas temperatures by thermally isolating a metal substructure using ceramic coatings, hold significant promise to greatly increase temperature capability without sacrificing other properties, especially if used with materials possessing higher intrinsic melting temperatures. The main drawbacks to TBCs involve loss of adhesion between the coating and base metal. The objective of this task is to explore several strategies for creating novel composite microstructures for ultra-high temperature applications with a desirable balance of properties. Included in this effort will be study of existing and surface-modified TBCs in order to develop a comprehensive numerical model of key failure mechanisms. This model will be used to enhance current life prediction methodologies and to enable a predictive scheme for developing microstructurally optimized TBCs. It is also expected that by including chemical and thermal gradients within the numerical framework, it will also be possible to explore concepts related to self-healing oxide reactions. The resulting material structures hold promise to yield revolutionary advances in material temperature capability.
OSU Research Team
Professor: S. Ghosh and M. WalterGraduate Student: H. Bhatnagar