Cover Picture: Ductile-to-Brittle Transition in Nanocrystalline Metals (Adv. Mater. 16/2005)

17_16/2005Uniaxial tensile studies concerning electrodeposited nanocrystalline face-centered cubic Ni and Ni–Fe alloys are reported on p. 1969 by Ebrahimi and Li. The nanograined metals display a transition in the deformation mechanism at a critical grain size. The cover shows that their fracture surfaces exhibited a ductile-to-brittle transition from the “cup–cup” (intragranular, ductile failure, dislocation controlled) (top panels) to “cup–cone” (intergranular, brittle fracture, probably due to breaking of atomic bonds) (bottom panels) characteristics at room temperature across this critical grain size value.

Read Full Text  | Table of Contents