Microstructure evolution of (Ti, Zr)C solid solution at the initial stage of phase decomposition

Abstract A solid solution of 90TiC–10ZrC (mol%) was prepared by spark plasma sintering and was partially decomposed into ZrC- and TiC-rich (Ti, Zr)C phases by heat treatment at 1573 K for 0.6–3.6 ks. The ZrC-rich phases were precipitated in the TiC-rich matrix with a coherent orientation relationship of ZrC-rich phase {100}//TiC-rich phase {100}. Phase decomposition started at the grain boundary and extended to the entire grain with increasing heat-treatment time. The Vickers hardness and fracture toughness increased as heat-treatment time increased to 3.6 ks.