MICROPLASTICITY AND INTERNAL FRICTION IN PURE IRON

We have studied the microdeformation behaviour of pure iron at low temperature (4K - 250K). Two thermally activated microdeformation stages are observed : one is associated to the α process observed by internal friction, the other is linked to the βα peak. Activation parameters determined for the α component are in good agreement with double-kink formation on non screw dislocations. βα component is due to dislocation depinning from an extended atmosphere