Dual composite architectonics: Behavior of ZrB2–SiC–TaB2 composites under abrasive conditions

Abstract

The influence of abrasive impact on ZrB2–SiC–TaB2 ceramic composites with homogeneous distribution of components in ZrB2 matrix and with «dual composite » structure (ZrB2–SiC)-(TaB2–SiC) has been studied. It was shown that at the same content of components the abrasive wear of the ceramic with the «dual composite » structure is significantly less than that of the composite with homogeneous distribution of single-phase components in a single-phase matrix. On the surface of the studied composites there were no furrows and grooves typical for the abrasive action on the material. At abrasive impact on ceramic composite with homogeneous distribution of components there was a formation of subsurface cracks with the subsequent tearing off of material segments with the size exceeding the size of inclusions in the matrix. Abrasive wear of ceramics with the «dual composite » structure at a high content of composite inclusions occurs by "erosion" of the matrix at the interface with composite inclusions with subsequent removal of inclusions. Composites with «dual composite » structure had higher residual strength compared to ceramic with homogeneous distribution of components. It was found that the difference in the character of abrasive wear of composites is largely in relation to the distribution of residual stresses formed due to the difference in the thermal linear expansion coefficients of the components.