MODIFICATION OF A DISORDERED NI3FE ALLOY SURFACE BY 50 KEV ZR ION-IMPLANTATION

It is well known that after ion implantation, microstructural changes are found at depths well beyond the range of the implanted ions, In th e present work samples of a disordered Ni3Fe alloy, implanted with fou r doses of a multicomponent ion beam (where the principal component wa s zirconium) in the range 0.6-6.0 x 10(17) ions cm(-2), have been stud ied by transmission electron microscopy with subsidiary measurements b eing made of microhardness and residual stress in some of the samples. It is found that the implanted zone becomes increasingly amorphous an d ZrO2 precipitates of increasing size appear as the implanted dose in creases. These are accompanied by high internal stresses evidenced by electron micro-diffraction and confirmed by X-ray diffraction measurem ents. Immediately below the implanted zone, the dislocation density is increased by 2-3 times, depending on the implanted dose, and decrease s monotonically down to a depth of about 10 mu m. This is accompanied by corresponding increases in microhardness and residual stress which becomes increasingly tensile with the implanted dose. (C) 1997 Elsevie r Science S.A.