Abstract
AX41 magnesium alloy (4Al-1Ca-balance Mg in wt.%) reinforced with short α -Al₂O₃ fibers (Saffil^®)has been deformed in compression at temperatures between 23 and 300 °C. The yield stress and the maximum stress decrease with increasing testing temperature. The influence of reinforcement on both characteristic stresses falls down with increasing temperature. Possible hardening and softening mechanisms are discussed. Stress relaxation tests were performed in order to reveal features of the thermally activated dislocation motion. Internal and effective components of the applied stress have been estimated. 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 connected with the rapid decrease of the internal stress with deformation temperature.

Key words
magnesium alloy based composite, compression deformation, stress relaxation test, thermally activated processes

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