Effect of TiO2 addition on the properties of Ti3Si(Al)C2 based ceramics fabricated by reactive melt infiltration

Abstract In this paper, Ti 3 Si(Al)C 2 based ceramics were fabricated by reactive melt infiltration (RMI) of TiC/TiO 2 preforms with liquid silicon. The microstructure, phase composition, and mechanical properties of the Ti 3 Si(Al)C 2 based ceramics have been investigated to understand the effect of phase composition of the preforms on the formation mechanisms of Ti 3 Si(Al)C 2 . The preforms with different content of TiO 2 infiltrated at 1500 °C with liquid silicon for 1 h were composed of Ti 3 Si(Al)C 2 , Al 2 O 3 , TiC, TiSi x Al y and residual Al. The prior generated Al 2 O 3 phases inhibited the dispersion of Ti 3 Si(Al)C 2 phases, resulting in the drastically grain growth of Ti 3 Si(Al)C 2 . Subsequently, the microstructure with gradually increasing Ti 3 Si(Al)C 2 grain size resulted in the decrease of the bending strength and fracture toughness of samples. When the content of TiO 2 reached 20 wt%, the bending strength reached the maximum, 326.6 MPa. The fracture toughness attained the maximum, 4.3 MPa m 1/2 , when the content of TiO 2 was 10 wt%.