In this research, the high-temperature mechanical, electrical and thermal properties of arc-melted W-based composites with a small amount of SiC additives were investigated. The high-temperature mechanical properties of tungsten were enhanced by the presence of the hard ceramic phase (W 5 Si 3 and W 2 C) and the interaction of dislocations. The ceramic phase also played a role in inhibiting the grain growth at high temperatures. The ultimate compressive strength (UCS) of the W with 1 wt% SiC (S1) was 968.9 MPa at 1273 K, which is three times that of pure W (291.9 MPa) at 1273 K, showing a significant enhancement in high-temperature strength . Both thermal conductivity ( κ ) and electrical conductivity ( σ ) decreased with the increasing of SiC addition. With increasing temperature, the σ decreased while the κ increased due to the intrinsic behavior of the ceramic phase in the composites.
Fully dense (Zr, Ti)B 2 -(Zr, Ti)C-SiC ceramics were prepared by reactive hot-pressing using ZrB 2 , TiC, and SiC as the initial materials for the first time. Effects of SiC addition on the microstructure evolution and mechanical properties were reported. The in-situ reaction between ZrB 2 and TiC as well as the SiC addition leads to the grain refinement. Besides, elongated (Zr, Ti)B 2 plate-like grains are obtained due to the occurrence of a transient liquid phase, which leads to the crack deflection in the matrix effectively. Mechanical properties are improved significantly due to grain-refinement and solid solution strengthening, and plate-like grains toughening effects. The ZrB 2 -10 mol%TiC composite with 10 mol% SiC additional exhibits good comprehensive mechanical properties of the hardness of 20.2 GPa, the flexural strength of 803 MPa, and the fracture toughness of 5.7 MPa m 1/2 .
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