Microscale plastic strain heterogeneity in slip dominated deformation of magnesium alloy containing rare earth

The propensity for the magnesium alloy ZEK100 to develop large microscale plastic strain heterogeneity has been quantified and correlated to microstructure using a combination of experiments and simulations. Conditions were specifically selected where deformation is dominated by slip rather than twinning. Digital image correlation measurements of intragranular plastic strain heterogeneity have revealed plastic strains as large as 5 times the macroscopic tensile strain. This strain amplification was found to be neither spatially correlated nor correlated with crystal orientation. Large local strains were, however, found to be statistically linked to proximity to grain boundaries. This suggests the importance of interactions between neighboring grains. To investigate this further full-field viscoplastic Fast Fourier Transform (VPFFT) crystal plasticity simulations were performed on synthetic microstructures representative of the material studied experimentally. It was found that both the macroscopic stress-strain response as well as the local plastic strain distribution could be well reproduced when the anisotropy in 'hardness' of the basal and non-basal slip systems was sufficiently high. Strain amplification was found to occur, in this case, to slip in regions of high basal slip activity adjacent to regions of high non-basal slip activity.