Phase Formation, Microstructural Evolution, and Mechanical Properties of Multi‐Phase Carbides (ZrHfVCrMoW)C

ABSTRACT A multi‐phase multi‐component carbide (Zr 1/6 Hf 1/6 V 1/6 Cr 1/6 Mo 1/6 W 1/6 )C 0.6 was synthesized via hot‐pressing sintering under 1650°C‒2000°C at an interval of 50°C for 1 h. A three‐stage solid solution process is revealed: the elemental segregation, emergence of a multi‐phase microstructure, and subsequent formation of a dual cubic phase carbide. Specifically, the elemental segregation dominates at 1650°C–1700°C. Subsequently, the (ZrHf)C‐rich and (V(CrMoW))C‐rich coupled with (CrMoW)C‐rich phases emerge, with the latter exhibiting a hexagonal structure. This hexagonal phase then binds with (V(CrMoW))C‐rich phase, resulting in a composite microstructure of (ZrHf)C‐rich and (VCrMoW)C‐rich phases. The sample sintered at 1900°C possess higher Vickers hardness (23.3 GPa) and flexural strength (474 MPa) over that sintered at 1800°C, primarily attributed to the solid solution strengthening. Conversely, the sample sintered at 1800°C demonstrates superior fracture toughness (5.4 MPa·m 1/2 ), attributed to the crack deflection caused by the plate‐like microstructure, effectively dissipating more fracture energy.