Synthesis and phase separation of (Ti,Zr)C

High-temperature toughening in ternary medium-entropy (Ta1/3Ti1/3Zr1/3)C carbide consolidated using spark-plasma sintering

“…The application of the EDX methods allowed us to observe the local chemical gradient in the metal atoms which becomes quite evident while examining the specimen deformed at 1800°C ( Figure 3). Overall, this may satisfy both the observations [15][16][17] and the highentropy alloy concept [7] in which local order-disorder peculiarities may control the macroscopic properties. It can be suggested that the appearance of these local gradients is due to the different diffusion rates for metal and carbon atoms in the pure metals or carbides [4].…”

“…It can be suggested that the appearance of these local gradients is due to the different diffusion rates for metal and carbon atoms in the pure metals or carbides [4]. According to the analysis by Andrievsky [4], the difference in diffusivities becomes rate controlling above 0.7 T melting (i.e., >2100°C), thus at lower temperatures the solubility limit [15][16][17] is a rate controlling factor. Furthermore, in general, binary systems of group IV and V metal carbides have a two-phase region below 2000°C, and the addition of the WC or VC carbides will expand this multi-phase region [18].…”

Phase decomposition of TiC−ZrC solid solution prepared by spark plasma sintering

“…1 shows the phase diagram of the TiCÀ ZrC system [12][13][14][15][16][17]. This system is a complete solid solution and has an immiscibility dome below 2400 K. The 90TiCÀ 10ZrC solid solution sintered at 2373 K had a uniform microstructure, and decomposed into two phases at the heat treatment temperature of 1573 K. This behavior was in good agreement with the phase diagram.…”

“…Levashov et al prepared TiÀ ZrÀ C alloys via a self-propagating high-temperature synthesis and reported the precipitation of submicron-sized particles after heat treatment at 1123À 1223 K; this enhanced the enhancement of the hardness from 16À 18 to 19À 23 GPa [15]. Borgh et al reported the phase-decomposition of TiCÀ ZrC solid solution powders with the formation of lamellar structures by heat treatment, resulting in a 9.5% increase in hardness [17]. The enhancement in hardness caused by heat treatment leading to microstructure refinement is associated with the Hall-Petch rule stating that strength increases with decreasing grain size submicronÀ micron range.…”

Synthesis and characterization of (Zr1/3Nb1/3Ti1/3)C metal carbide solid‐solution ceramic

“…In particular, MC solid‐solution ceramics have attracted considerable attention among these solid‐solution ceramics because of their extremely high melting points, high hardness, and high thermal and electric conductivity and are promising candidates for use in industrial, space, and armor applications . Until now, much effort has been devoted to the synthesis of the binary, ternary or quaternary MC solid‐solution ceramics. In particular, (U, Zr, Nb, Ti)C solid‐solution ceramics, as a member of MC solid‐solution ceramics, have attracted considerable attentions due to their extremely high‐temperature capability, high thermal and electric conductivity, low volatility, and good neutronic properties, which are promising candidates for use in nuclear industrial, space, and armor applications .…”