Finite Element Analysis of Mechanical Responses of Plasma Sprayed Composite Layers at the Structural Scale: Effect of the Pore Network Architecture

This study aims at better understanding the stress field within composite plasma sprayed layers submitted to strains since very few studies deals with this issue. In order to reach out this objective, finite element analyses (FEA) were conducted on domains resulting from the discretization of SEM high resolution pictures of coating structures.
Al₂O₃-13TiO₂ plasma sprayed coatings were considered for a demonstrative purpose. Several operating parameters permitted to manufacture coatings exhibiting several porous architectures, in terms of pore content, crack density and crack orientation. Numerical simulations show the very significant influence of the porous network architecture on the stress field within the layers.
Based on the same analyzed structures, other theoretical composite layer compositions were considered by modifying over a large range the intrinsic mechanical properties of the mixed phases. For the considered cases (i.e., a secondary phase content lower than 5 vol.%), simulations show the poor influence of the nature of the secondary phase on the stress field within the layers.
Beside these results, the paper proposes a generic methodology and points out its advantages and limits, emphasizing in particular the importance of the representative elementary volume (REV).