The effects of titanium ion implantation on structural and mechanical properties of single crystal and polycrystalline α-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 100nm) 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.

Nanoindentor techniques have been used to obtain the values of hardness and elastic modulus of α-Al2O3 polycrystalline implanted with metallic species at room temperature with 170 keV, doses ranging from 2×1016 to 2×1017 ions cm-2. After implantation, annealing was performed in the temperature range 600–1400°C. An attempt has been made to correlate the mechanical property modifications with physico-chemical analysis. Elastic and plastic properties of the implanted layers, of about 100 nm thickness, have been characterized by microprobe investigation. This has indicated that certain fluences and thermal annealing temperatures are favourable for the improvement of mechanical properties.

The effect of copper implantation on the mechanical properties, such as hardness, fracture toughness, and residual stress of alumina is addressed herein. The implantation conditions are conducted at room temperature on the polycrystalline alumina with doses ranged from 3 x 10(16) to 10(17) Cu cm(-2) (110 keV). The ion profile distribution was examined by Rutherford backscattering spectroscopy. Surface morphology was observed directly using scanning electron microscopy. Using the X-ray diffraction, we determined the crystallographic nature of the precipitates formed after heat treatment, The residual surface compressive stresses produced by these implantations, as determined by an indentation technique, ranged from 950 to 1720 MPa. Implantation caused a modification in the mechanical properties and an increase in the residual stress. The average residual compressive stress in the implanted region increases with fluence. (C) 1997 Elsevier Science S.A.

Ion implantation is known to be capable of modifying the surface and near-surface chemical and mechanical properties of solids pertaining to hardness, elastic modulus and fracture toughness. In this study polycrystalline alumina was implanted with and ions (110 keV) to a dose of at room temperature. Mechanical properties such as hardness and Young's modulus were determined using an ultra-low load microindentation hardness tester. With the Vickers indentation method, using different loads, the fracture toughness of the implanted layer was determined. The nature of the chemical phases were characterized by x-ray photoelectron spectroscopy (XPS). Implantation caused an increase in the hardness and the fracture toughness with no detectable effect on the Young's modulus. These modifications were attributed to microstructural changes caused by the implantation. The residual stresses were determined by a previously described indentation technique. They were found to be compressive in nature and ranged from 800 to 1800 MPa.

Polycrystalline tetragonal zirconia was implanted with 170 keV Ti ions to doses of 2 x 10(16) ions/cm(2) and 1 x 10(17) ions/cm(2). Localised plasticity, elasticity and fracture behavior have been investigated using nanohardness and microhardness indentation tests. Significant surface hardening has been observed at lower and higher doses. Post-implantation heat treatments produce precipitation reactions with associated hardness and elastic modulus changes, and reduced the fracture toughness at 1200 degrees C to pre-implant levels.

Polycrystalline α-Al2O3 was implanted at 170 keV with doses of 2 × 1016, 1 × 1017 or 2 × 1017 ions/cm2. The as-implanted samples were then annealed at 1000, 1200 and 1400°C. The mechanical properties, such as hardness (H) and Young's modulus (E) of these ion-implanted samples were characterized by a depth-sensing low-load indentation technique. The results showed that, with a low dose ion implantation followed by annealing at 1200°C, a significant increase in hardness and elastic modulus were found. For higher doses, where the implantation leads to the amorphisation of the material, the mechanical properties of the implanted alumina were inform to those of unimplanted alumina.

Non-stoichiometric titanium carbide layers TiCx (x = 0.26, 0.49 and 0.78) were synthesized by multiple energies ion implantation at the surface of titanium. The carbon concentration profiles obtained from RBS and SIMS measurements are almost flat over the whole implantation depth, in agreement with the simulation calculation. Grazing incidence X-ray diffraction shows the formation of TiC with an NaCl structure in all cases, in spite of the non-stoichiometric composition; nevertheless a small amount of carbon-titanium solid solution is detected on the TiC0.26 sample. The TiC lattice parameter increases with carbon concentration and the carbide layers are formed with small size crystallites. The XPS C1s and Ti2p peaks and the valence band spectrum show that the carbon is fully bonded to the titanium as carbide. Nanoindentation analysis indicates that the carbide layers present an elasto-plastic behaviour with the elastic part increasing with the carbon concentration. The same trend is observed for the hardness and Young's modulus of the TiCx layers.

Mechanical characterization by nanoindentation of implanted layers. The indentation study of applied surface layers or modified layers used in most high technology devices have led to the development of a new range of mechanical microprobes with which the mechanical characterization tests by nanoindentation give a continuous record of the indentation and elastic recovery using a triangular-base pyramidal indenter. Application examples show that nanoindentation is a powerful means of investigation and allows us to well characterize the mechanical properties of implanted layers.