Effect of Al2O3 on the microstructure and mechanical properties of Ti3AlC2/Al2O3 in situ composites synthesized by reactive hot pressing

Ti3AlC2/Al2O3 in situ composites with different Al2O3 contents were successfully synthesized from the powder mixture of Ti, TiC, Al and TiO2 by a reactive hot-pressing method at 1350 °C. The effect of Al2O3 on the microstructure and mechanical properties of the composites was investigated in detail. The results indicate that the as-fabricated products mainly consist of Ti3AlC2, Al2O3 and a small amount of TiC. With increasing the Al2O3 content, the flexural strength of Ti3AlC2/Al2O3 composites increase gradually, the fracture toughness reaches the peak value of 8.21 MPa m1/2 as the Al2O3 content increasing to 9 wt%, the hardness attains the maximum value of 10.16 GPa for 12 wt% Al2O3. The strengthening mechanism of the composites was also discussed.