Microstructure and mechanical properties of Ti۳SiC۲ MAX phases sintered by hot pressing

This study aimed to investigate the effect of sintering temperature on samples' microstructure and mechanical properties, including three-point flexural strength, Vickers hardness, and fracture toughness. Therefore, Ti۳SiC۲ samples were sintered under a vacuum atmosphere at a pressure of ۳۵ MPa for ۳۰ minutes at two temperatures of ۱۵۰۰ °C and ۱۵۵۰ °C by hot pressing. The microstructure obtained from the fracture cross-section of the samples shows that by increasing the sintering temperature to ۱۵۵۰ °C the microstructure of this sample becomes larger than the sintered sample at ۱۵۰۰ °C. Also, increasing the sintering temperature to ۱۵۵۰ °C causes the decomposition of Ti۳SiC۲ to TiC, which can be seen in the X-ray diffraction pattern (XRD). In addition, the relative density of the sintered sample at ۱۵۵۰ °C is ۹۸.۰۸% which is higher than that of the sintered sample at ۱۵۰۰ °C with the result of ۸۹%. On the other hand, the three-point flexural strength (۲۲۷.۵ MPa), the Vickers hardness (~۹ GPa), and the fracture toughness (۸.۶ MPa.m۱/۲) of the sintered sample at ۱۵۰۰ °C are higher due to the fine-grained structure.

Keywords:

MAX phase , Ti۳SiC۲ , Hot pressing , Microstructure , Mechanical properties