Nanoindentation of (Ti,Ta)(C,N)–Co cermets prepared by methods of mechanochemistry

• Four materials TixTa1 − xC0.5N0.5-20%Co of two compositions and one step and two step high energy milling have been prepared.
• Mechanochemical synthesis of (Ti, Ta) carbonitride grains was successfully achieved.
• Mechanical properties of the main constituents as well as of the composites were measured by nanoindentation.
• One step and two step milling lead to small differences on micro-level, the materials had comparable composite properties.

Four materials TixTa1 − xC0.5N0.5–20%Co of two chemical compositions (x = 0.9 and 0.95) and two high energy milling methods (one stage and two stage milling) have been prepared. Nano-hardness and elastic modulus for microstructure as a whole and for individual constituent phases (matrix and carbide grains) were obtained by instrumented indentation. Individual targeted indentations as well as grid nanoindentation technique were used to discern the individual constituents' properties. Maximum loads of 20 mN for individual phases and 300 mN for composite microstructure were applied. Materials with higher amount of Ti had larger grains but the milling procedure had stronger influence on the grain size. The two step milling resulted in finer microstructures but with a much wider grain size distribution. Final composite mechanical properties, however, were very similar. Hardness and indentation elasticity modulus of all materials were comparable within the errors of measurement.