35 - EFFECT OF AM PROCESSES ON THE COMPRESSIVE BEHAVIOUR OF 316L ARCHITECTED MATERIALS

Abstract

Due to their low-density and good dissipation properties, architected materials are increasingly used for various industrial applications. The emergence of additive manufacturing (AM) technologies has made it possible to modify the arrangement of the cells constituting the architected materials to achieve a targeted mechanical behavior. This study focuses on the mechanical behavior and the microstructure analysis of 2D-extruded periodic architected structures (honeycombs) in 316L obtained by AM processes. The 3D printing strategy and the morphology of the architectures produced will be studied. The compressive behaviour of these structures will be highlighted under out-of-plane quasi-static testing to evaluate the mechanical response of 3D printed parts filled with this type of structures. Laser Melting Deposition Powder (LMD-P) and Powder Bed Fusion (PBF) are the most widely used metallic AM processes and are therefore studied in this work. For this first phase of the study, the constitutive material behaviour law is characterized through tensile tests on standardized 3D-printed samples. In the second phase of the study, the out-of-plan crushing behaviour of simplified structures is investigated through compressive testing. Tubular structures are known for their good absorption properties. Their crushing mode is also similar to 2D honeycomb structures. Tubes are therefore fabricated by AM and tested under uni-axial compressive loading. Tests were carried out on a ZWICK Roell 250kN machine. The results show peak forces of between 32 kN and 36 kN for small displacements (1.5 mm). Simplified architected structures made by LMD-P and PBF are also tested under quasi-static compressive loading at a strain rate of 0.006 s-1. The obtained compressive curves start with a linear elastic region followed by a plastic plateau characterized by a significant undulation. With the captured images at different time, structure’s deformation phenomenon for different displacement imposed by the machine’s crossbar is observed. For the last phase of the study, the influence of filling pattern and manufacturing scenarii on the mechanical response of architected structures is investigated. Three-unit cells, denoted as, auxetic, tri-hexagonal and grid are printed by LMD-P and SLM and tested under compressive loading. The microstructures of the 3D-printed samples are analyzed during the various phases of the study using optical microscopy (OM) and scanning electron microscopy (SEM). Tensile fractures, porosities, grain morphologies, sizes and directions, and grain phases are observed. This study therefore presents the experimental methods developed and the results obtained at macroscopic and microscopic scales.

Speaker

Camille Buros

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Univ. Bordeaux, ESTIA-Institute of technology, BIDART, France

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Conference

35 - EFFECT OF AM PROCESSES ON THE COMPRESSIVE BEHAVIOUR OF 316L ARCHITECTED MATERIALS

Date/Time

21/03/2024

5:25 pm -5:45 pm

Location

Room 7