TY - JOUR
T1 - Shock-induced {11 2 1}→{11 2 2} double twinning in titanium
AU - Zhou, Ping
AU - Xu, Shun
AU - Xiao, Dawu
AU - Jiang, Chunli
AU - Hu, Yin
AU - Wang, Jian
N1 - Publisher Copyright:
© 2018 Elsevier Ltd.
PY - 2019/1
Y1 - 2019/1
N2 - Six twinning modes have been reported in α-titanium, including three extension twinning modes {10 1 2}, {11 2 1} and {11 2 3} and three compression twinning modes {11 2 2}, {11 2 4} and {10 1 1}. {10 1 2} and {11 2 2} twins are frequently observed without strong dependence on strain rate, while {11 2 1} and {11 2 4} twins are observed at high strain rate. These twinning modes and their interactions such as double twinning play significant roles in determining mechanical properties and texture evolution of α-titanium. In this work, we study double twinning associated with {11 2 1} primary twin. In order to activate {11 2 1} twinning, a split Hopkinson pressure bar (SHPB) device was adopted to conduct high strain rate (∼2600 s-1) compression of high purity titanium along the extrusion direction. We observed 453 {11 2 1}→{11 2 2} double twins but zero {11 2 1}→{11 2 4} double twins in six grains. Crystallographic analysis enables the classification of {11 2 1}→{11 2 2} double twins into Group I (29.5° < 1 100>), Group II (55°<5 5 10 3>), Group III (80.6°<1 1 00>) and Group IV(86.8°< 5 15 10 3>) according to the misorientation angle and axis pair. Groups I and II dominate in the proportion of experimentally detected double twins while Groups III and IV take a small proportion. We account for these phenomena according to apparent Schmid factor, modified deformation gradient accommodation, and twin nucleation via dislocation dissociation. The results demonstrate that the preferred secondary twinning mode and corresponding variant would, to the greatest extent, relax plastic deformation associated with the primary twinning.
AB - Six twinning modes have been reported in α-titanium, including three extension twinning modes {10 1 2}, {11 2 1} and {11 2 3} and three compression twinning modes {11 2 2}, {11 2 4} and {10 1 1}. {10 1 2} and {11 2 2} twins are frequently observed without strong dependence on strain rate, while {11 2 1} and {11 2 4} twins are observed at high strain rate. These twinning modes and their interactions such as double twinning play significant roles in determining mechanical properties and texture evolution of α-titanium. In this work, we study double twinning associated with {11 2 1} primary twin. In order to activate {11 2 1} twinning, a split Hopkinson pressure bar (SHPB) device was adopted to conduct high strain rate (∼2600 s-1) compression of high purity titanium along the extrusion direction. We observed 453 {11 2 1}→{11 2 2} double twins but zero {11 2 1}→{11 2 4} double twins in six grains. Crystallographic analysis enables the classification of {11 2 1}→{11 2 2} double twins into Group I (29.5° < 1 100>), Group II (55°<5 5 10 3>), Group III (80.6°<1 1 00>) and Group IV(86.8°< 5 15 10 3>) according to the misorientation angle and axis pair. Groups I and II dominate in the proportion of experimentally detected double twins while Groups III and IV take a small proportion. We account for these phenomena according to apparent Schmid factor, modified deformation gradient accommodation, and twin nucleation via dislocation dissociation. The results demonstrate that the preferred secondary twinning mode and corresponding variant would, to the greatest extent, relax plastic deformation associated with the primary twinning.
KW - Dislocations
KW - Double twinning
KW - High strain rate
KW - Titanium
UR - http://www.scopus.com/inward/record.url?scp=85052675132&partnerID=8YFLogxK
U2 - 10.1016/j.ijplas.2018.08.014
DO - 10.1016/j.ijplas.2018.08.014
M3 - Article
AN - SCOPUS:85052675132
SN - 0749-6419
VL - 112
SP - 194
EP - 205
JO - International Journal of Plasticity
JF - International Journal of Plasticity
ER -