Microstructures and Mechanical Behavior of Ti3SiC2/Al2O3-Ni Composites Synthesized by Pulse Discharge Sintering

摘要

High-purity Ti3SiC2 and Ti3SiC2/Al2O3-Ni composites with different Al2O3-Ni contents were fabricated using pulse discharge sintering (PDS) of a mechanical alloyed powder mixture. The synthesis process of monolithic Ti3SiC2 was studied through displacement temperature-time (DTT) curve, displacement rate-time and displacement rate-temperature diagrams obtained during the PDS process. It was found that TiC (x) and Ti5Si3C (y) are the intermediate phases and the PDS process completed after 20 min at 1350 A degrees C. The results showed that in Ti3SiC2/Al2O3-Ni composite, the Ni part of Al2O3-Ni leads to decomposition of Ti3SiC2 to TiC (x) , Ti5Si3C (y) and Ni(Si) (x) . No evidence was detected in the reaction between Al2O3 and Ti3SiC2. The density and hardness of the composites are higher than monolithic Ti3SiC2 due to the production of reinforcing phases. The composite showed lower flexural strength and higher compressive strength than monolithic Ti3SiC2.