The boundary structure of {10•1} deformation twins formed in commercially pure titanium during an initial pass of equal channel angular pressing processing was studied by transmission electron microscopy and high-resolution transmission electron microscopy. A new twinning mode with a twinning dislocation of b3/3 was identified using a dichromatic diagram method. The new mode of the {10•1} twin has substantially higher interface energy and accommodates more shear strain during deformation than the conventional b4 twinning mode. The deviation angle between the habit trace of the twin boundary and the theoretical twinning plane, K1, was dependent upon the density of twin dislocations.

Faceted Interfacial Structure of {10¯11} Twins in Ti Formed during Equal Channel Angular Pressing. Y.J.Li, Y.J.Chen, J.C.Walmsley, R.H.Mathinsen, S.Dumoulin, H.J.Roven: Scripta Materialia, 2010, 62[7], 443-6