Abstract
Magnesium alloys of AJ (Mg-Al-Sr) and AX (Mg-Al-Ca) series were deformed at temperatures between room temperature and 300 °C. Stress relaxation tests were performed in order to reveal features of the thermally activated dislocation motion.
The work hardening rate q = ds/de decreases with increasing stress and temperature. Analysis of the q-s plots revealed the hardening and softening mechanisms operating during the deformation.
Internal and effective components of the applied stress were been estimated. Very high values of the internal stress estimated at lower temperatures decrease rapidly with increasing deformation temperature.
The apparent activation volume decreases with increasing effective stress. The values of the activation volume as well as the activation enthalpy indicate that the main thermally activated process is most probably the glide of dislocations in non-compact planes..