The amorphous phase transition in irradiated NiTi alloy

Abstract

Abstract Observed supralinear dose dependence for the amorphous transformation during irradiation of NiTi is compatible with a cascade overlap model for heavy ion (2.5 MeV Ni+, 6 MeV Ta+++) irradiations. A model based on total defect build-up, however, is necessary to explain the amorphous transition induced by electron irradiation and can also be applied to heavy ion irradiation. The cascade effects in this latter model are manifested by non-uniform defect distribution in the lattice. The defect build-up model requires a high activation energy for interstitial migration which is not incompatible with recent findings. The form of the temperature dependence can also be rationalized using a defect build-up model (amorphous phase transition, heavy-ion irradiation, electron irradiation, NiTi, defect build-up, cascade overlap).