CAREER: Fundamental Micromechanics and Materials Dynamics of Thermal Barrier Coating Systems Containing Multiple Layers

University Of Alabama Tuscaloosa, Tuscaloosa AL

Investigators

Abstract

9984899 Weaver This research focuses on understanding the fundamental concepts controlling the mechanical properties of microconstituents in thermal barrier coatings (TBC) as a function of thermal exposure, both time and temperature. The specific goals of the proposed program are: (1) Characterize the properties of the macro- and micro-constituents of the TBC system as a function of thermal exposure using four model TBC systems; (2) Monitor and analyze the displacements of the TBC constituents during thermal cycling and isothermal oxidation coupled with mechanical strain; and (3) Develop physical and finite element models of TBC durability based on microstructural and mechanical evaluations of degradation mechanisms and processes. The specific objectives of the educational plan are: (1) Enhance the undergraduate curriculum by providing students with "hands on" training in the study of commercially viable thick films and coating materials; (2) Encourage undergraduate students from UA, Stillman, and FAMU to pursue graduate studies in Metallurgical and Materials Engineering; and (3) Increase diversity by attracting underrepresented minority students to undergraduate and graduate study at The University of Alabama. %%% The research results should provide fundamental understanding of the mechanisms contributing towards TBC failure and lead to the development of more accurate life prediction models. Thermal barrier coatings (TBC's) have been used for nearly three decades to extend the performance of aircraft turbines operating in hostile environments. Current TBC's are typically multilayer systems incorporating an insulating ceramic topcoat applied over a metallic bond coat; the latter is deposited directly on the surface of the component. While TBC's exhibit the desired insulating capability, it is the durability and reliability issues that have limited their application. A lack of fundamental data concerning the influence of microstructural degradation on the mechanical response of TBC's has impeded the development of accurate life prediction models. ***