J. Phys. IV France 11 (2001) Pr4-27-Pr4-32
Microstructure evolutions in pearlitic steels and Cu/Nb wires resulting from severe plastic deformation during drawingX. Sauvage1, L. Thilly2, 3 and D. Blavette1
1 Groupe de Physique des Matériaux, UMR 6634 du CNRS, Faculté des Sciences, Université de Rouen, 76821 Mont-Saint-Aignan cedex, France
2 Laboratoire de Physique de la Matière Condensée, INSA-UPS-CNRS, Complexe Scientifique de Rangueil, 31077 Toulouse cedex 4, France
3 Laboratoire National des Champs Magnétiques Pulsés, UMR du CNRS, 143 avenue de Rangueil, 31432 Toulouse cedex, France
The aim of this paper is to present recent microstructural investigations concerning two kinds of materials produced by industrial processes through high level of plastic deformations. To help in further understanding in the strengthening mechanism of such nanocomposite wires, the evolution of the microstructure was investigated using field ion microscopy (FIM), Transmission Electron Microscopy (TEM) and Three Dimensional Atom Probe (3D-AP). Niobium fibres and copper channels a few nanometers width with smooth interfaces were exhibited in the Cu/Nb wire. A deep interdiffusion of Cu and Nb was pointed out. This mechanical alloying induced by drawing is attributed to the strong increase of the interfacial energy of the system. Shear bands were also observed perpendicular to the wire axis. They were attributed to the tracks of moving dislocations in the (111) Cu plane, along the <110> direction. Cold drawn pearlitic steel wires were also studied. Because of the plastic deformation, cementite lamellae aligned themselves along the wire axis and are thinned down to a few nanometres. 3D-AP data clearly reveal partly dissolved cementite lamellae. As in the Cu/Nb system, the dissolution of cementite is discussed on the basis of thermodynamical arguments.
© EDP Sciences 2001