Decent ablative resistance, enhanced thermal conductivity and high mechanical properties of high-entropy (Hf, Zr, Ti, Ta)C-W composites

High entropy carbides (HECs) ceramics are promising candidates for high-temperature ablation-resistance materials. However, the limited thermal conductivity and mechanical properties still impede its capability to survive in extreme ablation environment. Here, we design the high entropy carbide Hf0.5Zr0.3Ti0.1Ta0.1C, denoted as HZTTC, integrated with refractory tungsten mesh. This composite remains intact subjected to ablation at 2500 degrees C. Its linear ablation rate (LAR) and mass ablation rate (MAR) achieve decent values of -1.75 mu m<middle dot>s(-1) and -0.149 mg<middle dot>s(-1)<middle dot>cm(-2). This decent ablation performance is characteristic of various ablation resistant oxides with unique morphologies, such as lamellar, flocculent, needlelike, and rod-shaped oxides. Surprisingly, the composite still reveals attractive ablation properties with the LAR of -0.75 mu m<middle dot>s(-1) and the MAR of -0.072 mg<middle dot>s(-1)<middle dot>cm(-2), even when the ablation temperature goes up to 2700 degrees C for 600 s. Moreover, the ceramic-metal composite achieves a high thermal conductivity of 25.72 W<middle dot>m(-1)<middle dot>K-1, demonstrating a 16.7 % enhancement to that of the pure HZTTC ceramic. Moreover, this composite also reveals a high hardness of 22.21 GPa and a fracture toughness of 5.64 MPa<middle dot>m(1)(/)(2). This decent ablation performance, high thermal conductivity and peculiar mechanical properties enable this composite to be a potential alternative for protecting hypersonic aircraft severing in extreme environments.