The role of back stress caused by precipitates on {101¯2} twinning in a Mg-6Zn alloy

In the present study, the effect of precipitate characteristics on {101¯2} extension twinning have been studied in a Z6 magnesium alloy. A strongly textured Z6 alloy plate was mechanically tested in twinning dominated orientation in solution treated and aged states. Optical microscopy, transmission electron microscopy (TEM) and visco-plastic self consistent (VPSC) modelling are used to examine the effect of precipitate characteristics on twinning. The yield stress was observed to increase by ∼80 MPa during ageing and it was estimated that CRSS for twinning increased by ∼29 MPa based on VPSC simulations. The increment of twin system strengthening can be attributed to back stress generated by elastically deforming particles.