Cellular materials made of stacked tubes: influence of the manufacturing process on the dynamic behavior of the constitutive material. part I: microstructure

Abstract : Cellular materials are very promising as lightweight aeronautical frames thanks to their superior specific mechanical properties such as impact resistance. However, because of the processing routes and heat treatments used in the production process, the material within the cell walls may behave differently from the bulk, and therefore the in situ mechanical properties are often unknown. The present work aims at investigating the link that exists between the processing of cellular architectures and the mechanical properties of their constitutive material. The cellular material studied is an Inconel® 600 tube stacking brazed together using a nickel-phosphorus alloy. The experimental works have been conducted in order to analyse the microstructures of Inconel® 600 tube stacking resulting from brazing and annealing heat treatment. In order to discuss the influence of the manufacturing process of tube stackings on the mechanical properties of their constitutive material, it has been proposed to perform uni-axial tensile tests on tubular specimens. Different material configurations (with or without heat treatments, with or without nickel-phosphorus coating) have been thus characterised and compared, involving both tensile tests from quasi-static to dynamic loads and electron back-scattered diffraction analyses (EBSD) performed on post-mortem specimens.