Publication alert
We are pleased to announce that our work on "Laser powder bed fusion of planar bi-metallic thermally auxetic lattice structures" has been published in CIRP Annals.
Multi-metal laser powder bed fusion (MM-LPBF) enables the production of metamaterial lattice structures with unusual mechanical properties within a single process. One interesting possibility is the realization of structures with zero thermal expansion (ZTE). In this study, planar reentrant lattices and triangular and curved unit cells are produced of stainless steel 316L and copper alloy CuCr1Zr via MM-LPBF. The samples were then heated while the thermal expansion was measured using digital image correlation. Despite the minor difference between the thermal expansion coefficients of the two materials, the lattice structure is shown to exhibit exceedingly low lateral expansion (on par with Invar 36) under fixed end constraints. When comparing the triangular and curved unit cells, it is show that curvature enhances the tunability of the thermal expansion converting stresses to internal strains. With this novel design and production method, it is possible to realize ZTE structures using conventional materials, which enhances producibility and avoids the use of exotic, rare, or toxic materials.
Link to the external page full paper.
