Superhard pcBN tool materials with Ti3SiC2 MAX-phase binder: Structure, properties, application

摘要

Superhard cutting tool materials were sintered in cBN-(Ti3SiC2-TiC) system via high pressure-high temperature method. Sintering was performed under the pressure 8 GPa in the 1400-2400A degrees C temperature range. The initial mixtures of three compositions were chosen with 90, 80 and 60 vol % cBN. The mixtures were prepared by mixing cBN (1-3 mu m) and Ti3SiC2-TiC (< 2 mu m). It was found, that upon sintering, the compositions of the obtained samples differed from the initial mixtures in all cases as a result of chemical reactions. Microstructure observations, phase composition estimation, and mechanical properties of the obtained tool materials were carried out. The results indicate that both the varying cBN content and the applied sintering conditions have a direct effect on the structure, properties, and kinetics of reactions.