Modification of a disordered Ni 3 Fe alloy surface by 50 keV Zr ion implantation Yurii P. Sharkeev a , Anthony J. Perry b, *, Daniel E. Geist c , Alexander I. Ryabchikov d , Alexei S. Tailashev e , Natalya V. Girsova a , Eduard V. Kozlov d a Institute of Strength Physics and Materials Science, Russian Academy of Sciences, 2/1 Pr. Akademicheskii, 634021 Tomsk, Russia b A.I.M.S. Marketing, 10921 Corte Calandria, San Diego, CA 92127, USA c Martin Lockheed, Mail Stop 9683, P.O. Box 179, Denver, CO 80201, USA d Nuclear Physics Institute at Tomsk Polytechnic University, 2a Lenin Str., 634050 Tomsk, Russia e Department of Physics, State Academy of Architecture and Building, 2 Solyanaya Sq., 634003 Tomsk, Russia Abstract It is well known that after ion implantation, microstructural changes are found at depths well beyond the range of the implanted ions. In the present work samples of a disordered Ni 3 Fe alloy, implanted with four doses of a multicomponent ion beam (where the principal component was zirconium) in the range 0.6–6.0 × 10 17 ions cm - 2 , have been studied by transmission electron microscopy with subsidiary measurements being made of microhardness and residual stress in some of the samples. It is found that the implanted zone becomes increasingly amorphous and ZrO 2 precipitates of increasing size appear as the implanted dose increases. These are accompanied by high internal stresses evidenced by electron micro-diffraction and confirmed by X-ray diffraction measurements. Immediately below the implanted zone, the dislocation density is increased by 2–3 times, depending on the implanted dose, and decreases monotonically down to a depth of about 10 mm. This is accompanied by corresponding increases in microhardness and residual stress which becomes increasingly tensile with the implanted dose.  1997 Elsevier Science S.A. Keywords: Disordered Ni 3 Fe; Ion implantation; Zr ion 1. Introduction It is well known that the influence of ion implantation is not restricted to the thin surface layer where the implant resides but extends to greater depths in the material [1–6]. The thickness of the implanted zone itself (IZ) does not exceed several tenths of a micron for the ion energies (20–200 keV) used usually for ion implantation. In contrast, the depth over which this ‘long-range effect’ occurs can vary from several microns up to tens of microns, or more. Changes are observed in the defect structure and phase state in this deeper-lying subsurface layer, but in spite of a large number of experimental investigations, the nature of the processes involved is not yet clear. In the present work, the results are presented of an experi- mental investigation into the structure and phases formed in the IZ and in the subsurface layers of a disordered polycrys- talline Ni 3 Fe alloy as a result of high dose ion implantation with zirconium ions. 2. Experimental The Ni 3 Fe alloy samples were annealed in argon at 800°C for 5 h and then quenched in water to obtain a disordered alloy [7] with a mean grain size 50 mm. Ion implantation was carried out in a repetitively pulsed ‘Raduga-2’ vacuum arc ion source [8] at an accelerating voltage of 50 kV to levels of 0.6 × 10 17 , 1.5 × 10 17 , 3.0 × 10 17 and 6.0 × 10 17 ions cm - 2 . The multicomponent cathode was primarily Zr (89.5 wt.%) with additions of C, N and O. The concentration profiles of the implanted samples were confirmed using Auger electron spectroscopy (AES). The phase composition of the IZ was studied in all sam- ples by electron diffraction of thin films and the defect structure of the subsurface layer was investigated in selected Thin Solid Films 308–309 (1997) 393–398 0040-6090/97/$17.00  1997 Elsevier Science S.A. All rights reserved PII S0040-6090(97)00590-7 * Corresponding author. Tel.: +1 619 6724543; fax: +1 619 6724450; e-mail: 76644.3330@compuserve.com