Dislocation network developed in titanium nitride by ion implantation

The present work is concerned with microstructural changes brought about by ion implantation into TiN as-deposited by classical chemical vapor deposit ion onto cemented carbide substrates. After implantation the ions occupy an implanted zone (IZ) extending to a depth of about 80 nm. The transmission: electron microscopy study shows that implantation can lead to the formatio n of subgrains ih the IZ within the original grain structure without changi ng the grain size. The energy carried by the ions affects the material to f ar greater depths and a dislocation network is formed below the IZ, termed the implantation affected zone (IAZ). The dislocation density in the IAZ as determined here by. x-ray diffraction depends on the total energy carried by the:implanted ions. There is a threshold level before a compressive resi dual stress is developed after which the:stress is proportional to the ener gy reaching values as high as 3-4 GPa. A mechanism is proposed for the deve lopment of the IAZ where an oscillating stress field is developed at the bo undary between the IZ and the IAZ and allows' the local emission of disloca tion fluxes in mezobands into the IAZ. (C) 1999 American Vacuum Society.