Tem Study Of Amorphous Alloys Produced By Ion Implantation

SUMMARY Ion implantation is a technique for introducing foreign elements into surface layers of solids. Ions, as a suitably accelerated beam penetrate the surface, slow down by collisions with target atoms to produce a doped layer. This non‐equilibrium technique can provide a wide range of alloys without the restrictions imposed by equilibrium phase diagrams. This paper reports on the production of some amorphous transition metal‐metalloid alloys by implantation. Thinned foils of Ni, Fe and stainless steel were implanted at room temperature with Dy+ and P+ ions at doses between 1018 and 1021 ions m−2 at energies of 20 and 40 keV respectively. Transmission electron microscopy and selected area diffraction analysis were used to investigate the implanted specimens. Radial diffracted intensity measurements confirmed the presence of an amorphous implanted layer. The peak positions of the maxima are in good agreement with data for similar alloys produced by conventional techniques. Only certain ion/target combinations produce these amorphous layers. Implantations at doses lower than those needed for amorphization often result in formation of new crystalline phases such as an h.c.p. phase in nickel and a b.c.c. phase in stainless steel.