MICROSTRUCTURE AND INDENTATION BEHAVIOUR OF MULTILAYER Ti-N FILM

The microstructure of Ti/TiN multilayer film was studied.It was shown by trans- mission electron microscopy of cross-sectional sample and respective secondary neutrals mass-spectroscopy depth profiling that the film has a periodic alternate multilayered structure:substrate /FeTi/Ti/Ti_2N/TiN/Ti_2N/Ti/Ti_2N/TiN...Ti/Ti_2N/TiN,where FeTi and Ti_2N were the transition layers formed during ion plating.Cross-sectional fracture surface of indentation samples had been obtained and studied with scanning electron microscopy.It was shown that the multilayer film deformed during indentation, formed an indentation pit and a pile-up of materials around the indentation pit.As the applied load increased deformation region extended beyond the film/substratc interface and into the substrate,the interlayer crack in the film and hole formation at the film /substrate interface were initiated.It is also shown that the multilayered Ti/TiN film offered better toughness in comparison with single layer TiN film.