M.S. Lee; N.M. della Ventura; A. Sharma; C. Tian; X. Maeder; T.S. Jun
Scripta Materialia 255 (2025) 116402
Uniaxial compression tests were performed on [0001]-oriented micropillars of pure titanium at cryogenic
temperature (T = 205 K). The interaction between {1122} twin variants activated in the micropillar was
investigated by transmission Kikuchi diffraction (TKD) in scanning electron microscope (SEM) and precession
electron diffraction (PED) in transmission electron microscope (TEM). Critical resolved shear stress (CRSS) for
{1122} twinning was estimated to be 471 ± 40 MPa. The sudden stress-drops were induced by twinning, and the
subsequent stress-strain response was dependent on the twin-twin interaction. The interaction between nano-size
twins resulted in the formation of abnormal twin-twin boundaries (TTBs), thereby suppressed the twin growth
and reduced the twinning-induced stress-drop. The complicated twin structures led to the strain-hardening after
the stress-drop.