IN-SITU SYNTHESYS AND PROPERTIES OF TiB2/Ti3SiC2 COMPOSITES

摘要

Based on thermodynamic analysis, TiB2/Ti3SiC2 composite ceramics were in-situ prepared by hot-pressing in an Ar atmosphere. The phase composition and microstructure of the materials were characterized by XRD and SEM. Effect of temperature on phase composition, sintering performance, microstructure and bending strength of the materials was investigated. The results showed that for the materials sintered at 1350°C ～1500°C, the main phases were Ti3SiC2 and TiB2. However, due to the volatilization of raw material Si at high temperature, small amount of TiC remained in all materials. With the increase of sintering temperature, the density and bending strength of the materials increased. Higher temperature was favorable to the grain growth of reinforcing phases and matrix. The materials sintered at 1500°C showed optimal microstructure and the highest bending strength of 741MPa. When sintering temperature is higher than 1550°C, the density and strength of the materials deceased gradually as a result of the decomposition of matrix Ti3SiC2.