The superhardness effect in TiC/B4C nanomultilayer film with interface reaction

Abstract

Abstract A series of TiC/B 4 C films have been prepared by magnetron sputtering techniques. The interface reaction, microstructure and mechanical properties have been characterized by X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy and nanoindention device, and the effect of structure evolution on the mechanical properties has been studied. The results show the interface reaction between TiC and B 4 C can react into TiB 2 and C. When the deposited B 4 C layer thickness is less than 0.5 nm, the multilayer will transit into TiC x /TiB 2 type film in which TiC x and TiB 2 should grow coherently with each other, and the film attains the highest hardness of 40.1GPa. Further increasing the deposited B 4 C layer thickness,the hardness will drop down quickly for the disruption of coherent growth structure, and the film should form sandwich structure. Based on the results, several basic rules have been proposed to design this kind of multilayers.