Transmission electron microscopy characterization of microstructure and TiN precipitation in low-energy nitrogen ion implanted V-Ti alloys

A detailed structural characterization of low-energy, nitrogen implanted V5at.%Ti alloys is presented. Samples were nitrogen-implanted at 1.2 kV and 1 mA/cm(2), up to a dose of 4x10(-19) ions/cm(2), at temperatures between 400-575 degrees C. Alloys were analysed by transmission electron microscopy. Depending on the implantation temperature, the ion beam treatment dramatically changes the microstructure of the material. Partial amorphization, nitride precipitation and dislocations are imaged. A clear correlation between the microstructure of the implanted layer and the reported improvement in the tribological properties has been demonstrated. For implantation at 575 degrees C a nanocomposite layer forms at the sample surface, where the reinforcement particles are TiN precipitates.