Effect of heat treatment on the decomposition of TiC–ZrC solid solutions by spark plasma sintering

Abstract

TiC–ZrC solid solutions at ZrC composition of 5–90mol% were consolidated by spark plasma sintering of TiC and ZrC powders. The phase decomposition behavior by heat-treatment at 1273–2273K was investigated. TiC–ZrC solid solutions with 10–70mol% ZrC decomposed into TiC- and ZrC-rich phases after heat treatment at 1473–2273K for 3.6ks. The decomposition resulted in the formation of nodular structures several tens to hundreds nanometers in length with coherent crystal orientation relationship of the TiC-rich phase {100} // ZrC-rich phase {100}. The Vickers hardness and fracture toughness increased with increasing heat-treatment temperature and reached maximum values of 26GPa and 3.0MPam1/2, respectively, for 80TiC–20ZrC heat treated at 1873K.