Microstructure changes induced by low-energy high-temperature nitrogen ion implantation on vanadium-titanium alloys

摘要

A detailed structural and tribological characterization of unimplanted and low-energy, nitrogen implanted V5at. %Ti alloy is presented. Samples were nitrogen-implanted at 1,2 kV and 1 mA/cm2, up to a dose of 1E19 ions/cm2, at a temperature of 673 K. Alloys were analyzed in cross-section by transmission electron microscopy and electron dispersive x-ray. Depending on the deep from the surface, the ion beam treatment dramatically changes the microstructure of the material. Partial amorphization of the implanted alloy in a region of 250-800 nm in deep is observed, following by a fully crystalline region at 800-1000 nm in deep, where TiN precipitates and dislocations are imaged. A clear correlation between the microstructure of the implanted layer and the reported improvement in the tribological and mechanical properties has been demonstrated.