Mechanical responses of plasma sprayed coatings from residual stress measurements and finite element analysis: Effect of the pore network architecture
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2011-01-01
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Universidad de Tarapaca
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This study aims a better understanding residual stress and stress field within composite plasma sprayed coatings submitted to strains. In order to reach out this objective, residual stress techniques can be implemented for measurements during elaboration of coatings and finite element analyses (FEA) can be conducted on domains resulting from the discretization of Scanning Electron Microscopy (SEM) high resolution pictures of coating structures. TiO 2-Cu and Al 2O 3-13TiO 2 plasma sprayed coatings were considered for demonstrative purposes regarding residual stress measurements and effect of the pore network architecture, respectively. Several operating parameters permitted to manufacture coatings exhibiting different magnitude of residual stress and several porous architectures, in terms of pore content, crack density and crack orientation. Residual stress determined from measurements of deflection during elaboration of TiO 2-Cu coatings allow to identify their nature while numerical simulations show the very significant influence of the network architecture on the stress field within the Al 2O 3-13TiO 2 coatings. Based on the same analyzed structures, other theoretical compositions were considered in the finite element analyses by modifying the intrinsic mechanical properties of the phases. For the considered cases, simulations show the poor influence of the nature of the secondary phase on the stress field within the coatings. 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).