In situ characterization of the deformation and failure behavior of non-stochastic porous structures processed by selective laser melting

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 528; no. 27; pp. 7962 - 7967
• Main Authors: Gorny, B., Niendorf, T., Lackmann, J., Thoene, M., Troester, T., Maier, H.J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.10.2011; Elsevier
• Subjects: Applied sciences; Cellular; Deformation; Digital image correlation; Direct manufacturing; Elasticity. Plasticity; Exact sciences and technology; Failure; Fractures; Lasers; Lattice structures; Lattices; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Melting; Metals. Metallurgy; Microstructure; Optimization; Selective laser melting; Direct manufacturing; Lattice structures; Selective laser melting; Microstructure; Digital image correlation; Scanning electron microscopy; Heat treatment; Cracking; Cubic shape; Cellular material; Digital image; Porous material; Titanium base alloys; EBSD; Compressive stress; Strain distribution; Property structure relationship; Fracture mode; Structural analysis
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2011.07.026

► The present study focused on deformation behavior and failure mechanisms in lattice structure produced by selective laser melting (SLM). ► It is demonstrated that heat treatments can be used to increase the energy absorption of an SLM-processed structure. ► An in situ testing procedure was introduced, where local strains were calculated by digital image correlation ► Shear failure could be predicted by localization using Tresca strains. ► The approach employed provides a means to understand the microstructure-mechanical property–local deformation relationship. Cellular materials are promising candidates for load adapted light-weight structures. Direct manufacturing (DM) tools are effective methods to produce non-stochastic structures. Many DM studies currently focus on optimization of the geometric nature of the structures obtained. The literature available so far reports on the mechanical properties but local deformation mechanisms are not taken into account. In order to fill this gap, the current study addresses the deformation behavior of a lattice structure produced by selective laser melting (SLM) on the local scale by means of a comprehensive experimental in situ approach, including electron backscatter diffraction, scanning electron microscopy and digital image correlation. SLM-processed as well as heat treated lattice structures made from TiAl6V4 alloy were employed for mechanical testing. It is demonstrated that the current approach provides means to understand the microstructure-mechanical property–local deformation relationship to allow for optimization of load adapted lattice structures.