Green laser powder bed fusion based fabrication and rate-dependent mechanical properties of copper lattices

Additive manufacturing of pure copper (Cu) via laser-powder bed fusion (L-PBF) is challenging due to the low energy absorptivity under infra-red laser. As a result, 3-dimensional architectures, known for excellent load-bearing and energy absorption capabilities, have not been fabricated in pure Cu, so far. This study, for the first time, Cu lattice structures are fabricated through laser-powder bed fusion (L-PBF) with green laser (k = 515 nm). Structural and microstructural analysis confirm that the lattice structures consist of well-defined unit-cells and show dense microstructure. The deformation behavior is investigated under a wide range of strain rates from 0.001 /s to 1000 /s. The stress-strain curves exhibit a smooth and continuous deformation without any post-yield softening, which can be attributed to the intrinsic mechanical properties of Cu. Correlated with post-mortem microscopy examination, the ratedependent deformation behavior of pure Cu lattice structures is investigated and rationalized. The current work suggests that the complex Cu architectures can be fabricated by L-PBF with green laser and are suitable for dynamic loading applications.& COPY; 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study demonstrates the fabrication of copper lattice structures using green laser in laser-powder bed fusion, which have well-defined unit cells and dense microstructure. The deformation behavior of these structures under different strain rates is investigated and rationalized, suggesting their suitability for dynamic loading applications.