Design Framework for Optimized Multifunctional Coatings

Abstract

Abstract An ICME (Integrated Computational Material Engineering) and lifing model/method is developed for optimizing multifunctional coatings Atmospheric Plasma Spray (APS) process of metallic TBC (Thermal Barrier Coating) system. Optimized TBC performance was achieved by minimizing thermal conductivity and residual stresses/strains during APS utilizing multiphysics-based multi-objective topology optimization methodology, and virtual design of experiment (DOE), surrogate meta modeling methodology. Thermal conductivity and residual strains were minimized 41% and 27%, respectively, for APS 8YSZ TBC with MCrAlY bond over Waspaloy substrate considering as variables yttria (mol.%), number of layers, total thickness, substrate initial temperature, and coating initial temperature. Durability and Damage Tolerance (D&DT) analysis of Metallic bonded TBC dogbone specimen was performed using Multi-Scale Progressive Failure Analysis (MS-PFA). The objective was to determine the Remaining Useful Life (RUL) of Metal/TBC (8YSZ, Bond, Inconel-718) system under Low Cycle Fatigue (LCF) in-service loading at 900°C. The multi-scale multi-layer TBC modeling considered Thermal Growth Oxidation (TGO) in bond coat, and recession of top coat. Prediction was validated by Rig testing; TGO measurement Progressive damage analysis revealed that failure is due to tension and out of plane shear, delamination growth due to when recession penetrates bond. The results showed that predicted fatigue life compared well to experimental observations.