  Lattice dynamical methods used to predict phase-transformations in crystals
typically evaluate the harmonic phonon spectra and therefore do not work in
frequent and important situations where the crystal structure is unstable in
the harmonic approximation, such as the $\beta$ structure when it appears as a
high-temperature phase of the shape memory alloy (SMA) NiTi. Here it is shown
by self consistent {\it ab initio} lattice dynamical calculations (SCAILD) that
the critical temperature for the pre-martensitic $R$ to $\beta$
phase-transformation in NiTi can be effectively calculated with good accuracy,
and that the $\beta$-phase is a result primarily of the stabilizing interaction
between different lattice vibrations.
