Abstract
Abradable coatings are widely used in aerospace turbine engines to improve seal performance between rotating and stationary parts and thus the engine efficiency. As they are elaborated by thermal spraying of composite powders, these materials are highly heterogeneous. Their behaviour in working conditions is quite complex and not fully understood. This study contributes to a better knowledge of the mechanical behaviour of a range of abradable coatings. Finite Element calculations were derived from the analysis of micrographs and allowed to estimate the coefficients of an anisotropic elastic law of behaviour. Several models were investigated in the case of an AlSi-PE (Polyester) coating. As the PE % appeared to be a determinant factor, its influence was quantified ranging from 0% to 100%, using virtual micrographs deduced from the original ones. The computed Young's moduli Ex (in coating longitudinal direction) were quite consistent, considering the hypotheses made. An empirical relationship giving the variation law of Ex versus the PE % was suggested and applied to predict the modulus Ex of a real coating, which was close to the measured value.
