THE INFLUENCE OF UNIAXIAL DEFORMATION ON THE MARTENSITIC PHASE-TRANSFORMATION IN LI AND LIMG

The influence of a uniaxial deformation on the low-temperature phase t ransformation in Li and in LiMg system has been investigated bg neutro n scattering techniques. The results of the experiments performed indi cate that an elastic [001] compression of the BCC matrix promotes the phase transition. An investigation of the TA(1) [110] phonon branch in Li shows that the mild [001] compression of a Few 0.1% decreases the phonon frequencies by several percent. Furthermore, a severe plastic d eformation induces the formation of a disordered polytype phase instea d of the 9R structure.