The deformation mechanism of body-centered cubic nanocrystalline tantalum with grain sizes of 10–30nm was investigated by nano-indentation, scanning electron microscopy and high-resolution transmission electron microscopy. In a deviation from molecular dynamics simulations and existing experimental observations on other body-centred cubic nanocrystalline metals, the plastic deformation of nanocrystalline Ta during nano-indentation was controlled by deformation twinning. The observation of multiple twin intersections suggested that the physical mechanism of deformation twinning in body-centred cubic nanocrystalline materials was different from that in face-centered cubic nanocrystalline metals.

Deformation Twinning during Nano-Indentation of Nanocrystalline Ta. Y.M.Wang, A.M.Hodge, J.Biener, A.V.Hamza, D.E.Barnes, K.Liu, T.G.Nieh: Applied Physics Letters, 2005, 86[10], 101915 (3pp)