Dislocation-solute Atom Interaction in Aluminum Studied by Amplitude-dependent Internal Friction

In order to get the information on the force-distance curve for the interaction between a dislocation and a solute atom, amplitude-dependent interna1 friction was measured at 1.7 30 K on Al-100 at ppm Zn and Al-50 at ppm Zn single crystals. The temperature dependence of applied strain under a constant decrement is the same for two concentrations with high accuracy. The data were analyzed by the thermally assisted break-away model for dislocations assuming several potential forms. In conclusion, a modified Cottrell expression is proposed, in which dislocation core structure is taken into account, and the model can explain the temperature dependence of applied ~train~satisfactorily. The core radius of dislocation is estimated to be about 3 A.