S.G. Kang; B. Bellon; L.K. Bhaskar; S. Zhang; K. Ding; A. Götz; J. Wirth; B. Apeleo-Zubiri; S. Kalácska; M. Jain; A. Sharma
Acta Materialia (2025)
Metallic micrometamaterials exhibit high specific strength and energy dissipation capability. However, the mechanical response of these materials under extreme thermomechanical environments is largely unexplored. Here, we uncover new mechanisms of deformation in metallic microlattices across thermal and mechanical extreme environments. Copper microlattices were fabricated via localized electrodeposition process with submicron spatial resolution. The microlattices, for the first time, were compressed at cryogenic (-150 °C) and room temperatures at high strain rates upto 100 s-1. The copper microlattices with micron sized grains and randomly oriented growth twins exhibit unique temperature and strain rate dependent deformation behavior during compression, resulting in enhanced energy dissipation. Compression of copper micropillars, equivalent in diameter and length to the struts of the microlattice, revealed substantial shifts in deformation mechanisms from dislocation slip to mechanical twinning depending on the temperature and strain rate. This comprehensive understanding provides insights into designing metallic micrometamaterials for extreme thermomechanical applications.