Synthesis and spark plasma sintering of Ti5Si3-Mo powders with core-shell structure

Core-shell Ті₅Si₃-Mo powders were successfully synthesized by reducing of ammonium molybdate (para) tetrahydrate with hydrogen and glycerol, respectively. As a result, the Ti₅Si₃ core was coated with submicron and nanosized Mo particles. The morphology and microstructure of the synthesized powders were studied scanning electron microscopy along with local chemical analysis. Phase analysis was performed using X-ray diffraction. The synthesized powders were densified by spark plasma sintering (SPS) at a temperature of 1500 °C. It was shown that powders with a core-shell structure are densified up to a temperature of 1330 °C, while the mechanical mixture of commercial powders at this temperature only begins to densify. The hardness (HV20) of the obtained composites was also investigated. Compressive strength investigation at room temperature shows 5.5 % plastic strain and ultimate strength of about 3 GPa as well as fractographic studies have shown the presence of a pseudo-brittle fracture mechanism for the metal matrix composite (MMC), which was sintered by SPS of the core-shell Ti₅Si₃-Mo powder synthesized by reduction with glycerol.