Study of the Effect of Grain-Boundary Misorientation on Slip Transfer in Magnesium Alloy Using a Misorientation Distribution Map

The microstructure evolution of a Mg-Gd-Y alloy was studied using uniaxial tension combined with an electron backscatter diffraction technique. The results show that large amounts of slip transfer phenomena can be observed around the grain-boundary area after tension, and the activation of these slips depends largely on the misorientation of grain boundaries. The Mg-Gd-Y alloy shows almost randomized grain-boundary misorientation, but transferred slip traces were preferred at boundaries with misorientation around the [0001] axis between 0-30 degrees. Theoretically, materials with a higher fraction of slip transfer at the grain-boundary area would improve the ductility. Upon comparing the two groups of magnesium alloy with different grain-boundary misorientation distributions, the one with more grain boundaries favored for slip transfer achieved higher elongation during a tension test. Therefore, in addition to weakening the texture, adjusting the misorientation of the grain boundaries appears to be a new method to improve the ductility of magnesium alloys.