Abstrakt
The dynamics of the deformation mechanisms activated in cast binary magnesium-gadolinium (Mg-Gd) alloys with respect to the concentration of Gd was studied with in-situexperimental methods. Alloys were characterized by random texture and homogenous microstructure.Acoustic emission (AE) technique was recorded simultaneously during compression tests to determine the dominant deformation mechanism activated in different stages of the deformation.
Deformation test were repeated in the chamber of scanning electron microscope (in-situSEM). The development of the microstructure was concurrently followed by secondary electrons and electron back-scatter diffraction (EBSD).
The main goal of these measurements was to identify the activated slip systems in particular stages of the deformation and the progress of twin volume fraction. Results of the combination of AE and in-situSEM indicate higher activity of non-basal slip systems with increasing Gd content.
Lateral growth of twins decreases also with higher Gd concentration as a result of decreased mobility of twin boundaries caused by solute Gd atoms. High speed camera was used to investigate the dynamics of twinning, mainly to estimate the velocity of twin propagation.
The results clearly indicate that the rate of twin propagation is in order of 10 m/s.