Structural transformations in metals at high compression ratios
Moscow State Institute of Steel and Alloys (Technology University), Leninskii prosp. 4, Moscow, 117936, Russian Federation
An analysis of crystal structure stability against homogeneous deformation is carried out for simple and transition metals with body-centered cubic (bcc) and face-centered cubic (fcc) lattices under pressure. It is shown that at high
compression ratios a crystal lattice can turn unstable against shear deformations, leading to new lower-symmetry structures. To analyze these structures, the Landau theory of phase transitions with finite deformation tensor components as order parameters is applied. A comparison is made with experimental data
on high-pressure phases. Prospects are discussed for using the suggested approach to explain structural transformations in solids at high pressures.