Nanoporous Ta - Mechanical properties and deformation mechanisms

VAZQUEZ, N.; RAMALLO, J.I.; FUERTES, M.C.; RUESTES, C. J.

Seehotel Weingärtner Lake Bostal, Germany

Simposio; Nanoporous 2023 - Fourth International Symposium on Nanoporous Materials by. Alloy Corrosion; 2023

Refractory-based nanoporous metals combine the excellent mechanical performance of the base material with virtues inherited from its nanoscale structure. Despite their tremendous potential, studies probing their mechanical properties are still very limited. In this work, we explore the mechanical properties and deformation mechanisms of nanoporous Ta (np-Ta). np-Ta particles (~0.4 relative density and 30 – 200 um dia.) with an avg. ligament size in the range of 100 – 300 nm were subjected to nanoindentation tests using a Berkovich indenter. Particles were glue to the sample holder, and measured without the need to include them in a resin, and polished. Their indentation modulus and hardness were calculated from the load - displacement curves obtained. In addition, molecular dynamics simulations of np-Ta particles under compression were performed. Our results indicate that plasticity takes place by the nucleation of dislocations on ligament surfaces. At the early stages of deformation, dislocations propagate across the ligaments and annihilate when reaching a free-surface. Later on, for larger strains, deformation proceeds in a dislocation-accumulation scenario.