Structure of grain boundaries with 30°[0 0 0 1] misorientation in dynamically recrystallized magnesium alloys

Abstract

In dynamically recrystallized magnesium alloys and other metals with hexagonal close-packed (HCP) structures, grain boundaries (GBs) with 30°[0001] misorientation relationship have frequently been observed with an intensity peak in the misorientation angle distribution. This phenomenon has sometimes been attributed to the formation of coincident site lattice (CSL). But the structure of this type of GBs has not been studied in detail. In this work, we performed CSL analysis for this type of GBs in a magnesium alloy, by employing molecular dynamics simulations. The GB energy was calculated as well. The results show that the 30°[0001] symmetric grain boundary (GB) has a high GB energy and the GB structure significantly deviates from the Σ13a CSL. Possible mechanisms for the formation of this type of GBs were discussed.