The role of nanotwin lamellae in enhancing thermal stability of nanostructured materials was examined. Nanostructured copper with varying densities of twins was generated by controlling the deformation strain rate during severe plastic deformation at cryogenic temperatures. While the nanostructured materials produced under cryogenic conditions were characteristically unstable even at room temperatures, their stability was markedly improved when a dense dispersion of nanotwins was introduced. Observations of the role of nanotwins in pinning grain and sub-grain structures suggested an interfacial engineering approach to enhancing the stability of nanostructured alloys.

Stabilizing Nanostructured Materials by Coherent Nanotwins and Their Grain Boundary Triple Junction Drag. C.Saldana, T.G.Murthy, M.R.Shankar, E.A.Stach, S.Chandrasekar: Applied Physics Letters, 2009, 94[2], 021910