Microstructure and mechanical properties of Ti_(3)(Al,Ga)C_(2)/Al_(2)O_(3) composites prepared by in situ reactive hot pressing

摘要

In this study,Ti_(3)(Al,Ga)C_(2)/Al_(2)O_(3) composites were successfully synthesized by in situ hot pressing at 1350°C for 2 h using Ti,Al,TiC,and Ga_(2)O_(3) as raw materials.X-ray diffraction and scanning electron microscopy were used for characterizing the phase identities and microstructures of the sintered composites.The dependence of the Vickers hardness and flexural strength on the Al_(2)O_(3) content was found to be in single-peak type.Ti_(3)(Al_(0.6),Ga_(0.4))C_(2)/10.3vol% Al_(2)O_(3) composite exhibited significantly improved mechanical properties.Vickers hardness and flexural strength of the composite reached 6.58 GPa and 527.11 MPa,which were 40% and 74% higher than those of Ti_(3)AlC_(2),respectively.Formation of solid solution and incorporation of second phase of Al_(2)O_(3) resulted in the opposite influence on the fracture toughness.Finally,the hardening and strengthening mechanisms were discussed in detail.