NANO-INDENTATION STUDIES OF TWINNED MAGNESIUM SINGLE CRYSTALS

摘要

Nano-indentation measurements have been performed on {10-12}<10-11> twin and adjacent matrix regions of deformedmagnesium single crystals and the hardness values were analyzedby the Oliver-Pharr method. Although the hardness differencebetween the twin regions and the adjacent matrix wasinsignificantly small, the hardness values showed orientationdependence regardless of the twins’ size and variants. Thisobservation can be interrupted by texture- softening resulting fromthe lattice reorientation in the twin regions. In contrast, theexperimental evidence for the Basinski hardening mechanism in{10-12}<10-11> twins, which is an increase in strength/hardnessas a result of dislocation contributions within twin area, was notobtained from this experiment. This presentation providesframework for the discussion of the hardening/softening effect of{10-12}<10-11> twinning on the plastic flow in single crystallinemagnesium and quantitative values for hardening parameters usedin the crystal plasticity modeling.