Boride ceramics with high strength at ultra-high temperatures

Boride-based ceramics have strengths of 500-600 MPa up to 1500°C when doped with suitable secondary phases and densified using the proper sintering technique. However, in order for these materials to be employed in the ultra-high temperature regime, exploration of their performance at higher temperatures is necessary. Here, we present the strength behavior at temperatures up to 2100°C and show the effects of microstructure tailoring in terms of secondary phases, grain morphology and grain size. Strengths exceeding 1 GPa have been achieved at 1800°C and analysis showed this behavior was due to sub-grain refinement which occurred as a consequence of intragranular plasticity under load.