Micromechanics of Ti(C,N)-FeNi composites: statistical analysis and flow stress determination for the FeNi binder

The outstanding mechanical and tribological properties exhibited by cemented carbides results from the combination of two phases with different local properties. However, direct assessment of the small-scale response of these materials is rather limited in open literature. This is particularly true, regarding experimental analysis on the influence of phase nature, crystal orientation and interfacial adhesion strength on hardness for composites, different from plain WC-Co systems. The present work aims to conduct a systematic micro- and nanomechanical study of the mechanical integrity of two Ti(C,N)-FeNi systems with different ceramic and binder content. It is attempted by combining massive nanoindentation and statistical analysis to extract the intrinsic hardness for each constitutive phase. After that, using the intrinsic hardness for the metallic FeNi binder and the Tabor's equation, the flow stress can be determined. Experimental results are found to validate the evidence of mechanical isotropic for the Ti(C,N) phase. Moreover, they permit to identify and account the strengthening of the plastic-constrained FeNi binder; a critical input parameter for hardness and toughness modeling.