Abstract
The temperature variation of the separation of Shockley partials of single dissociated dislocations in Cu-6·44 at. % Al and Cu-13·43 at. % Al has been measured by means of in situ thermal cycling experiments in a high-voltage electron microscope; a weak-beam high-resolution imaging technique was used for the observations. The variations of the partial separation on changing the temperature was analysed by taking into account such factors as temperature dependence of shear modulus, the solute impedance effect, the Suzuki effect and short-range order which may give rise to the variation of partial separation, in addition to the intrinsic temperature dependence of the stacking-fault energy γ. The intrinsic temperature dependence of γ was determined in the range 77 K to 1020 K for Cu-13-43 at. % Al and in the range 120 K to 723 K for Cu-6·44 at. % Al. The nature of the intrinsic temperature dependence of γ is discussed.