Abstract
The lattice invariant shear of the martensitic transformations in the Ti36.5Ni48.5Hf15 alloy was determined as a (001)B19′ compound twin by in-situ TEM technique. The morphological features of the (001)B19′ twin lamellas were revealed in detail. The shapes of the martensite variants were either the form of triangular, quadrilateral or lath plates. The mosaic-like morphology of the martensite variants corresponds to the cross section of the triangular, quadrilateral prisms, or the lath plates. The vertical section of the lath plates appears with a spear-like feature. The self-accommodation of the triangle, lateral prisms and the lath plates is usually composed of four martensite variants. There are 18 four-variants combinations of the mosaic-like martensite variants.
