Optical metallography and transmission electron microscopy were used to investigate the formation and microstructure of strain localization bands and deformation twins in single crystals deformed by rolling. On the basis of these investigations, and a theory of martensitic transformations based upon the concept of cooperative thermal vibration of coherent objects (close-packed planes) in crystals, a new mechanism of twinning was suggested. This involved the forward plus reverse (B2 → B19 → B2) martensitic transformation, with the reverse transformation occurring via an alternative transformation system. It was shown that, by using this mechanism, it was similarly possible to describe twinning in the crystal lattice of the B2 phase with twin planes having different ({112}, {113}, {332}) Miller indices, and the formation of strain localization bands with low-angle misorientations.

Mechanism of Deformation and Crystal Lattice Reorientation in Strain Localization Bands and Deformation Twins of the B2 Phase of Titanium Nickelide. A.N.Tyumentsev, N.S.Surikova, I.Y.Litovchenko, Y.P.Pinzhin, A.D.Korotaev, O.V.Lysenko: Acta Materialia, 2004, 52[7], 2067-74