Temperature dependent critical stress for {<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"><mml:mrow><mml:mn>10</mml:mn><mml:mover accent="true"><mml:mn>1</mml:mn><mml:mo>¯</mml:mo></mml:mover><mml:mn>2</mml:mn></mml:mrow></mml:math>} twinning in magnesium micropillars at cryogenic temperatures

Single-crystal magnesium micropillars (5 µm diameter) have been fabricated using focused ion beam (FIB) milling and loaded in compression along the [21¯1¯0] direction at cryogenic temperature (T = 184 K) three different strain rates: 10-4, 5 × 10-3 10-1 s-1. The stress-strain curves post-mortem analyses reveal predominance of {101¯2} twinning. critical stress required for twinning is detected to be significantly higher compared with that previously reported temperatures same rates. From experimental data, dependence rate sensitivity activation volume unveiled observed constant linearly dependent T, respectively. By considering energy (Q) terms stress-dependent dislocation motion equation proposed by Schoeck, twinning, Q determined 174 kJ mol-1 T < 273 K 72 above.