In situphase changes in a Fe-40 at.% Al ordered alloy during ion implantation: T.E.M. study

Abstract

The radiation damage and disordering phenomena produced at room temperature during Fe⁺, Bi⁺⁺ and Xe⁺ ion implantations in a Fe-40 at.% A1 ordered alloy were studied by in situ transmission electron microscopy. Progressive, but not total disordering was achieved in the thinnest areas of the specimens during high fluence implantations (> 10¹⁵ ions/cm²). Simultaneously, the athermal formation of a new phase occurs in the case of Fe⁺ and Bi⁺⁺ implantations. The diffusion-less mechanism suggests a martensitic like transformation. During post-implantation annealing, reordering and long-range order domain growth occurred in the temperature range up to 570 K. Above 670 K another phase appeared, which was stable up to 1070 K. The results are discussed and compared with those obtained on melt-quenched or neutron irradiated specimens of the same alloy.