Mechanical properties of titanium implanted polycrystalline alumina and sapphire determined by nanoindentation

The effects of titanium ion implantation on structural and mechanical properties of single crystal and polycrystalline alpha-alumina were studied. Grazing angle X-ray diffraction (GXRD) allowed the identification of structural alterations. Surface morphology was observed directly using scanning electron microscopy (SEM), elastic and plastic properties of the implanted layers (of which the thickness is about 100 nm) have been characterised by microprobe investigation. Results of the hardness and Young's modulus, determined by nanoindentation technique and the physicochemical study, have allowed us to correlate elastic and plastic property modifications with microstructure state of implanted ceramics and after annealing. Ion implantation plus thermal annealing were found to be favourable for the improvement of mechanical properties. (C) 1998 Elsevier Science Limited and Techna S.r.l.