In-situ analysis of slip transfer and heterogeneous deformation in tension of Mg-5.4Gd-1.8Y-1.5Zn alloy

Slip transfer is influential in determining damage nucleation of polycrystalline material. The interactions between dislocations and grain boundaries (GBs) was investigated using in-situ tension test in a multi-directionally forged Mg-5.4Gd-1.8Y-1.5Zn (wt%) alloy. It was found that strain accommodation of individual grains by means of slip occurred more easily than slip transfer when several slip systems were operable. The basal-basal slip transfer occurred when the GB misorientation was smaller than 34.2°, whereas basal-pyramidal type took place when the crystallographic misorientation was larger than 48.8°. The product of Luster-Morris m′ factor and the sum of the Schmid factors of the two correlated slip systems indicated that the threshold for basal-basal slip transfer may exist, however, basal-pyramidal slip transfer shows no such threshold and is more complicated. These results presented here demonstrated that besides the geometrical alignment, the deformation details (such as the number of operable slip systems) and stress state in each individual grain must be considered.