Structural, mechanical, electronic properties, and Debye temperature of quaternary carbide Ti3NiAl2C ceramics under high pressure: A first-principles study* *Project supported by Fujian Science & Technology Innovation Laboratory for Energy Devices of China (21C-LAB) (Grant No. 21C-OP-202013), the National Natural Science Foundation of China (Grant No. 12064027), the International Science and Technology Cooperation Program of China (Grant No. 2015DFA61800), and the

Abstract

Quaternary carbide Ti3NiAl2C ceramics has been investigated as a potential nuclear fusion structural material, and it has advantages in certain aspects compared with Ti2AlC, Ti3AlC2, and Ti3SiC2 structural materials. In this paper, quaternary carbide Ti3NiAl2C ceramics is pressurized to investigate its structural, mechanical, electronic properties, and Debye temperature. Quaternary carbide Ti3NiAl2C ceramics still maintains a cubic structure under pressure (0–110 GPa). At zero pressure, quaternary carbide Ti3NiAl2C ceramics only has three bonds: Ti–Al, Ni–Al, and Ti–C. However, at pressures of 20 GPa, 30 GPa, 40 GPa, 60 GPa, and 70 GPa, new Ti–Ni, Ti–Ti, Al–Al, Ti–Al, and Ti–Ti bonds form. When the pressure reaches 20 GPa, the covalent bonds change to metallic bonds. The volume of quaternary carbide Ti3NiAl2C ceramics can be compressed to 72% of its original volume at most. Pressurization can improve the mechanical strength and ductility of quaternary carbide Ti3NiAl2C ceramics. At 50–60 GPa, its mechanical strength can be comparable to pure tungsten, and the material changes from brittleness to ductility. However, the degree of anisotropy of quaternary carbide Ti3NiAl2C ceramics increases with the increasing pressure. In addition, we also investigated the Debye temperature, density, melting point, hardness, and wear resistance of quaternary carbide Ti3NiAl2C ceramics under pressure.