The mesoscopic characterization of the microhardness of superhard films of TaN, TaC and Ta(N,C)

摘要

The preparation and structure of superhard films of TaN, TaC and Ta(N,C) have been researched extensively since the 1980s because of their important properties, such as high melting point, high hardness, oxidation resistance, corrosion resistance, high chemical stability etc. [1-4]. These properties are certainly related to the material structure [5,6]. Among these, the hardness is a measure of a material's ability to resist applied load against plastic deformation. The microhardness, Hv, can be regarded as being determined by the bonding type and strength, which are reflected in the shear modulus, and, at the same time, as being determined by the configuration parameters of crystal defects, such as the dislocation substructure and so on [7, 8]. However, the establishment of the quantitative constitution equation between the microhardness and the dislocation substructure has been attempted by many people - even in dreams - in the past 40 years. The objective of the study reported here was to resume this kind of effort. Of course, the dislocation substructure parameter must first be measured, then the parameters can be taken into a certain quantitative constitutive equation.