Nonbasal Slips and Twins of Magnesium Coarse Grains

Abstract

Nonbasal slips and twins were investigated at elevated temperatures (20∼347°C), using coarse grained magnesium tensile specimens produced by the strain-anneal method. The results obtained were as follows: (1) In crystals with such orientations as χB (the angle between the basal plane and the stress axis)≈0°, a {10\bar11}〈11\bar20〉 pyramidal slip occured even at 120°C, a temperature much lower than the Schmid’s critical temperature (225°C); (2) In some case, {10\bar10}〈11\bar20〉 prismatic slips were observed as the secondary nonbasal slips; (3) No nonbasal slip was observed at room temperature; (4) The pyramidal slip bands were always wavy, mainly owing to the accompanying basal slip; (5) While {10\bar12} type primary twins were always observed independently of orientation, {10\bar11} (or {30\bar34}) twins occured in those crystals of χB≈0°.