Plastic deformation of stochiometric NiTi in the martensitic state was
investigated. Four structural conditions were established until a dis
ordered a phase is formed by very high amounts of deformation. Changes
of the course of martensitic cycles and R phase formation were analys
ed, until transformability clases at epsilon > 40%. Thermally activate
d reactions are able to recreate martensitic retransformatibility in t
he highly deformed condition.