THE FORMATION OF HIGH ANGLE GRAIN BOUNDARIES DURING THE PLASTIC DEFORMATION OF MAGNESIUM AND MAGNESIUM ALLOYS

This paper deals with the formation of grain boundaries during plastic deformation of pure magnesium, a matrix type magnesium alloy (Mg-6Zn-0.65Zr), and the two-phase Mg-8.1Li-4.2Al alloy. It is shown that the main process responsible for the generation of recrystallized grains is the formation of subgrains under small deformations followed by their transformation into high-angle boundaries. It is established that an important role in the development of dynamic recrystallization is played by twinning. The effect of the character of crystallographic slip on the generation of new grains is also considered. The two-phase magnesium alloy was used to show that the overlap of heterogeneous transformation with dynamic recrystallization results in the formation of interphase boundaries