Room-temperature plasticity and size-dependent mechanical responses in small-scale B1-NbC(001) single-crystals

We report on the mechanical responses of NbC(001) single-crystals subjected to nanoindentation and in situ scanning electron microscopy based uniaxial microcompression tests at room-temperature. Using X-ray diffraction photoelectron spectroscopy, we determine that as-purchased bulk NbC is a 001-oriented, B1-structured, single-crystal with lattice parameter 0.4446 ± 0.0002 nm C/Nb ratio ∼0.99. From experiments performed crystal using Berkovich diamond indenter, measure an elastic modulus 495 14 GPa indentation-depth (h) dependent hardness decreasing from 31.0 1.2 h = 0.2 µm 26.4 0.4 0.9 µm. During compression cylindrical pillars top diameters D between ∼0.25 ∼0.75 µm, observe strain hardening, increasing yield strengths D, surprisingly extensive plastic deformation strains exceeding 2% up 30% larger-size pillars. Electron characterization compressed reveal slip traces characteristic {110}〈11¯0〉 {111}〈11¯0〉 systems. suggest unexpected activation facilitates plasticity NbC(001).