Ultrahigh‐temperature tensile behaviors of ZrB ₂ –SiC ceramics

Abstract ZrB 2 –SiC ceramics are the potential candidates for the ultrahigh‐temperature thermal protection materials of sharp‐bodied reentry and hypersonic vehicles. However, their ultrahigh‐temperature mechanical behaviors have been rarely reported. In the present work, an ultrahigh‐temperature testing method for the tensile properties of ceramics is proposed. The tensile behaviors of ZrB 2 –20 vol% SiC are studied up to 1950°C in air and to 2050°C in nitrogen atmosphere for the first time. The tensile stress–strain curves, Young's modulus, and tensile strength are obtained. The microstructure evolutions, including crystallization of sintering aids, grain recombination, and grain oxidation, are observed, and their effects on the tensile properties are analyzed. The mechanisms controlling the tensile behaviors at ultrahigh temperatures are revealed. The maximum operating temperature of ZrB 2 –SiC ceramics has been identified.