Hardness response to the stability of a Ti( plus N) solid solution in an annealed TiN/Ti( plus N)/Ti mixture layer formed by nitrogen ion implantation into titanium

摘要

The presence of a Ti(+N) solid solution in nitrogen implanted commercially pure titanium grade II was investigated using XRD, TEM and nanoindentation. A TiN/Ti(+N)/Ti mixed layer was observed. Postimplantation annealing in the temperature stability range of TiN (300-600 degrees C) showed a falling amount of Ti(+N) and microstrain relaxation. A gradual decrease in hardness was observed, from 27 GPa for an implanted sample without annealing to 21 GPa for an annealed sample at 600 degrees C. The redistribution of interstitially located nitrogen was found to be responsible for the decrease in hardness. There was an improvement in hardness by a factor of 9-7 in comparison with the non-implanted sample. (C) 2018 Elsevier B.V. All rights reserved.