Cellular materials made of stacked tubes : influence of the manufacturing process on the dynamic behaviour of the constitutive material Part II : mechanical behaviour

Abstract : The purpose of these works is to study the link that exists between the manufacturing process of cellular architectures and the mechanical properties of their constitutive materials. It is a preliminary work to the mechanical characterisation of regular tube stackings which focuses on the evolutions of both microstructures and mechanical properties of Inconel 600 resulting from brazing heat treatment and diffusion of the brazing compounds. Reference is made to Inconel 600 tube stacking brazed using a nickel-phosphorus alloy in view of aeronautical applications, for instance impact resistance. The paper interests more precisely the experimental characterisation of the mechanical properties faces to dynamic loads. Different material configurations are thus characterised and compared, involving both tensile tests from quasi-static to dynamic. Results show that a viscous effect on the mechanical behaviour of Inconel 600 exists in the tubes before heat treatment. However, the heat treatment acts such as a recovery treatment on the plastic properties of the tube material eliminating viscous effects. Electron back-scattered diffraction (EBSD) post-mortem analyses of the tensile specimens show a strong texture too, resulting from the tensile loading and a quite homogeneous intragranular misorientation is observed inside the grains, reflecting large plastic deformations. EBSD analyses are presented in more details in a paper by Davoine et al. Different mechanical properties have also been identified according to Johnson-Cook's model. They will be used in future works addressing the experimental characterisation and the finite-element modelling of the mechanical behaviour of tube stackings.