INFLUENCE OF PLASTIC-DEFORMATION ON THE MARTENSITIC PHASE-TRANSFORMATION IN LITHIUM

The influence of plastic deformation on the phase transition behavior of lithium is investigated by neutron scattering techniques. Plastic d eformation about 30 degrees above the transformation temperature (74 K ) does inhibit the phase transformation even down to low temperatures. On the other hand, below the phase transition temperature plastic def ormation favors the phase transformation. The amount of the low-temper ature phase is increased but the structure obtained after severe plast ic deformation is no longer 9R. The diffraction data indicate the form ation of a polytype where the stacking sequence of close packed planes is disordered.