UHTC ceramics derived from B₄C and MAX phases by reactive sintering

In this work, the influence of three MAX phases (Ti₃SiC_2, Ti₂AlC, and Cr₂AlC) on the densification and final properties of dense composites from Ultra-High Temperature Ceramics (UHTC) family was studied. Addition of the MAX phases resulted in the formation of secondary boride phases due to chemical reactions between boron carbide and MAX phase. Mentioned phases were utilized for reduction of sintering temperature of the final composite material. It decreased the sintering temperature up to 800 °C when compared to pure B₄C. Additionally, the phase composition and derivative mechanical properties were investigated to evaluate differences between final composite materials. All obtained materials remarkably increased their fracture resistance (K_IC) from 33 to 100%. The mechanical properties of B₄C were either retained (Ti₃SiC₂) or decreased in terms of Vickers hardness and Young's Modulus (Ti₂AlC and Cr₂AlC). Systems with Ti₃SiC₂ appeared to possess significant potential for application, also when compared to UHTC systems of similar purpose.