Additive manufacturing has greatly widened the possibilities to design smart metallic metamaterials with properties that are clearly superior to those of their constituent alloys [1]. In particular, strut-based 3D printed lattices are being currently optimized for applications in the lightweighting of structural components, as well as in the optical, electromagnetic, and biomedical fields. However, optimizing lattice design is a complex endeavor, as it involves a deep understanding the coupled effects of a large number of parameters at the material, unit cell and structure levels. It has now been well established that the lattice topology has a major influence on its elastic and plastic properties. However, the influence of isolated microstructural parameters of the base material such as the grain size, the grain boundary network, or the precipitate distribution, has still not been as clearly explored.

This talk will present some recent work [2,3] related to the effect of gamma´´ precipitation on Inconel 718 lattices with a wide variety of architectures fabricated by laser powder bed fusion. In particular, both single-crystalline and hybrid topologies will be contemplated. It will be shown that microstructure has a decisive influence on the deformation and failure mechanisms, as well as on the strain localization patterns. The effect of microstructure is, however, highly dependent on topology, and thus the coupling of these two design variables must be taken into account when designing additively manufactured metamaterials for structural applications.

References

[1] T. Maconachie, M. Leary, B. Lozanovski, X. Zhang, M. Qian, O. Faruque, M. Brandt, Mater. Des., 2019, 183, 108137.

[2] S.Banait, X. Jin, M. Campos, M.T. Pérez-Prado, Scripta Mater., 2021, 203, 114075.

[3] S.Banait, C. Liu, M. Campos, M.S. Pham, M.T. Pérez-Prado, Mater. Des., 2022, 224, 111294.