Effect of precipitates on the dominant active slip systems in Mg-4.5Zn (wt.%) alloy
Biaobiao Yang, Jun Wang, Mahmoud Reza Ghandehari Ferdowsi, Qi Chao, Xiang Gao, Yunping Li, Yuman Zhu, Matthew Barnett, Javier LLorca
Abstract
The dominant active slip systems during plastic deformation of an extruded Mg-4.5Zn (wt.%) alloy with and without β 1 ′ precipitates were investigated by means of advanced electron back-scattered diffraction techniques and transmission electron microscopy . Planar slip traces were found in 92% of the grains with slip traces in the sample without precipitates and, among them, the primary active slip systems were basal <a> slip and pyramidal II <c + a> slip. However, non-planar slip traces were observed in 76% of the grains with slip traces in the sample with precipitates, and among them, prismatic <a> slip exhibited the highest activity, followed by pyramidal II <c + a> slip. The change in the dominant active slip systems with precipitation was attributed to the strong hardening induced by β 1 ′ precipitates on basal <a> slip. This favoured the cross-slip of basal <a> slip dislocations to prismatic plane and plastic deformation progressed by the glide of prismatic <a> slip dislocations parallel to the precipitates.