METALLOGRAPHIC INVESTIGATIONS OF NITROGEN-IMPLANTED TITANIUM-ALLOYS

Pure titanium and Ti-6Al-4V samples were implanted with N+ with an ion energy of 180 keV and doses between 1 and 6.10(17) cm(-2). A change i n the etching behaviour of the material due to the ion implantation wa s observed. Spherical sections were prepared for metallographic examin ation in order to investigate radiation effects. With this technique i t is possible to visualize ion-and dose-dependent changes within the i mplanted zone and the depth of the modified zone can be also measured. Nitrogen implantation into Ti-6Al-4V results in depth-dependent preci pitation of TiN, which can be identified by its typical golden colour. Further chemical analyses of the implanted layers were carried out wi th X-ray photoelectron spectroscopy. The depth profiles confirmed the precipitation of TIN. Nanoindentation measurements revealed an increas e in microhardness after ion implantation into Ti-6Al-4V. Correlations between the changes in hardness and the results of metallographic and chemical analyses are discussed. (C) 1998 Elsevier Science S.A.