Recrystallization and Grain Boundary Sliding in a Magnesium Alloy

Abstract

DURING tensile deformation of magnesium and its dilute alloys in the temperature range 100°–350° C, cells form preferentially close to the grain boundaries1. Afterwards irregular boundary migration occurs and evidence has been presented for the grain boundaries being pinned at their intersections with the cell walls2. This migration results in an increase in grain boundary area and thus the driving force must arise from the difference in stored energy between neighbouring grains. It is unlikely that sliding can occur to any appreciable extent at these irregular boundaries and in these circumstances it is probable that the shearing forces in the vicinity of the grain boundaries are accommodated by increases in the degree of misorientation across the cell walls. Eventually the irregular migration leads to primary recrystallization2–6 along the old grain boundaries and an example is illustrated in Fig. 1.