Shear band formation during nanoindentation of EuB6 rare-earth hexaboride
Published in Communications Materials, 2022
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Abstract: Research on rare-earth hexaborides mainly focuses on tuning their electronic structure from insulating-to-metallic states during high pressure experiments. However, the structural evolution that contributes to their mechanical failure is not well understood. Here, we examine the pressure-induced structural evolution of a model rare-earth hexaboride, EuB6, during nanoindentation. Transmission electron microscopy reveals that nanoscale amorphous shear bands, mediated by dislocations, play a decisive role in deformation failure. Density functional theory calculations confirm that amorphous bands evolve by breaking boron-boron bonds within B6 octahedra during shear deformation. Our results underscore an important damage mechanism in hard and fragile hexaborides at high shear pressures.
Recommended citation: Karre, R., Shen, Y., Song, S., Hu, Y., Lahkar, S., Wang, X., An, Q. and Reddy, K.M., 2022. Shear band formation during nanoindentation of EuB6 rare-earth hexaboride. Communications Materials, 3(1), p.24. https://doi.org/10.1038/s43246-022-00246-2