Structures of Monoclinic Phases in Titanium Nickelide: III. Transformation Cascade B2 -> M

摘要

An experimental neutron diffraction pattern was obtained for a polycrystalline sample of titanium nickelide of composition Ti_(50)Ni_(50) at a temperature of 60 K in the homogeneity range of the monoclinic martensitic phase. Its identification was performed using the DBWS program; good agreement was obtained between the experimental and calculated neutron scattering intensity profiles; numerical values of the lattice parameters and atomic coordinates in the unit cell were determined. The structure of this monoclinic phase is shown to differ from the B19' structure described in literature; its unit cell has other dimensions, it is oriented differently with respect to the parent cubic lattice of the B2 phase, it contains a greater number of atoms.