Simulation of the high temperature impression of thermal barrier coatings with columnar microstructure

The phenomena governing the durability of thermal barrier coatings (TBCs) are affected by their high temperature mechanical properties: especially the mechanisms of material removal upon particle impact. Some high temperature properties can be explored using an impression test described in a companion article. The utility of the test is contingent upon a method for deconvoluting aspects of the stress/strain response from load-displacement measurements. A numerical procedure having this attribute is described, and applied to TBCs with a columnar microstructure. The method elucidates the extent of the plastic deformation and densification as well as the column distortions caused by the impression. It is also capable of exploring the deformation heterogeneities observed experimentally, such as shear bands, by embodying salient constituent properties, such as the column width, contact friction, and inter-columnar friction. Comparisons with measurements provide some understanding of the plastic response of several thermal barrier systems. (C) 2003 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.