|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Deformation and Damage Mechanisms in High Temperature Ni, Co and Fe-based Superalloys
||The Performance of a New γ' Bond Coating on Single Crystal René N5 in Sustained Peak Low-cycle Fatigue
||Marissa Lafata, David J. Jorgensen, Akane Suzuki, Don M. Lipkin, Tresa M Pollock
|On-Site Speaker (Planned)
Bond coats (BCs) for single crystal turbine blades are traditionally designed primarily for oxidation protection with minimal consideration of mechanical properties. High strength γ'-Ni<SUB>3</SUB>Al BCs are resistant to rumpling and improve the spallation lifetime in furnace cycle tests compared to (Pt,Ni)Al when a ceramic thermal barrier coating is present. However, γ’ coatings tend to grow thicker oxides than β-phase coatings. Finite element modeling indicates creep-resistant BCs are beneficial in mitigating oxidation-assisted fatigue crack growth but also that crack penetration rates scale with oxide thickness. Fatigue specimens of René N5 with a γ’ coating of composition Ni-24Al-2.6Cr-2.5Ta-0.7Hf (at.%) were compressively loaded in isothermal strain controlled tests at 1093 °C. Analysis of fatigue damage using scanning electron microscopy, EBSD and EDS, provides insights into oxide-filled cracks that propagate through the layers. The performance of the γ’ BC suggests a delicate balance between strength and oxidation behavior is required for optimal system performance.
||Planned: Supplemental Proceedings volume