Crack mechanics of functionally graded coating/substrate systems. Final report, 1 February 1995--31 January 1998
This 3-year research program focuses on micromechanics and fracture mechanics analyses of cracking in functionally graded coating/substrate systems used in turbine engines and wear-related applications. Functionally graded materials (FGMs) are new advanced composites whose composition varies from place to place according to performance requirements. Recent developments of FGMs have demonstrated that functionally graded materials have the potential to enjoy a wide range of thermal and structural applications including thermal barrier coatings, wear, oxidation and corrosion resistant coatings and metal/ceramic joining. The objectives of the study include: establishing a fundamental understanding of the relationship between coating composition and performance, quantifying the influence of coating gradation, evaluating the effect of metal plasticity and crack bridging, and predicting the fracture driving forces and fracture resistance curves. Emphases in this study is placed on delamination fracture and multiple cracking in FGM coatings. The fundamental understanding gained from this study may enable one to select coatings at the component design stage. The systematic model predictions and design charts for the thermomechanical behavior of the coating/substrate systems may provide guidance to the gradation design of functionally graded coatings. This study thus can have a significant impact on the developments of functionally graded materials in turbine engine and wear related applications.
- Research Organization:
- Johns Hopkins Univ., Baltimore, MD (United States)
- OSTI ID:
- 339481
- Report Number(s):
- AD-A-356866/XAB; CNN: Contract F49620-95-1-0120; TRN: 90740442
- Resource Relation:
- Other Information: PBD: Jan 1998
- Country of Publication:
- United States
- Language:
- English
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