In-situ TEM study of <c plus a> dislocations in Mg-Y alloys

In this work, in-situ TEM compression has been carried out to observe the nucleation and movement of dislocations in Mg-Y alloys. The effect of Y contents (0.4 wt% and 4 wt%) on the dislocation behaviour was studied. It was found that a larger yielding stress was needed to activate the slip in the alloy containing 4 wt% Y. The edge dislocations on the pyramidal II plane in Mg-0.4Y alloy assumed an extended locked configuration with line direction parallel to the basal plane, while non-edge segments remained mobile during the compression. In Mg-4% Y alloy, dislocations assumed an oval shape and were associated with enhanced cross-slip activities without the long edge segments parallel to the basal plane frequently seen in the Mg-0.4Y alloy.