The dislocation mechanisms which were responsible for the mechanical properties of nano-scale multi-layers were studied by using heavily-drawn pearlitic steel wires as an example. Two specific types of dislocation source were observed during in situ transmission electron microscopic straining experiments. One dislocation source operated at large interlamellar spacings, via dislocation propagation in ferrite around cementite islands. The other source consisted of dislocations which bulged into ferrite from the interfaces. this was more likely to operate at low interlamellar spacings. The constitutive law of the material was governed by a balance between the dislocation multiplication and annihilation rates. It predicted a linear dependence of the flow stress upon the reciprocal of the interlamellar spacing.

Specific Dislocation Multiplication Mechanisms and Mechanical Properties in Nanoscaled Multilayers - the Example of Pearlite. M.Janecek, F.Louchet, B.Doisneau-Cottignies, Y.Bréchet, N.Guelton: Philosophical Magazine A, 2000, 80[7], 1605-19