Recent Neutron Scattering Studies on the Premartensitic State of BCC-Based Metals and Alloys

In the present article, we review the recent neutron scattering studies on the anomalous behaviours found in the premartensitic bcc-based metals and alloys, i.e. alkali metals, group-IV metals, β-phase alloys, Ni-base alloys and others such as T1 and group-III metals. Lattice dynamical anomalies appearing on the [110]TA 1 and [111]LA phonon dispersion relations of these materials are discussed from a view point of the martensitic transformation mechanism with referring briefly to theoretical studies. We also consider characteristics of anomalous elastic scatterings associated with the ω phase formation