The structural properties, elastic anisotropy, electronic structures and work function of D0₂₂-type Al₃TM (TM = Sc, Ti, V, Y, Zr, Nb, La, Hf, Ta) are studied using the first-principles calculations. The results indicate that the obtained formation enthalpy and cohesive energy of these compounds are in accordance with the other calculated values. It is found that the Al₃Zr is the most thermodynamic stable compound. The mechanical property indexes, such as elastic constants, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and Vickers hardness are systematically explored. Moreover, the calculated universal anisotropic index, percent anisotropy and shear anisotropic factors of D0₂₂-type Al₃TM are analyzed carefully. It demonstrates that the shear modulus anisotropy of Al₃La is the strongest, while that of Al₃Ta is the weakest. In particular, the density of states at Fermi level is not zero, suggesting that these phases have metal properties and electrical conductivity. More importantly, the mechanisms of correlation between hardness and Young’s modulus are further explained by the work function. Finally, the experimental design proves that D0₂₂-Al₃Ta has an excellent strengthening effect.

In the present study, the effects of pressure on the structure, elastic properties and electronic structure of DNTF compounds are studied using the first principles method. It is found that pressure has a great influence on lattice constants. When the pressure reaches 80 GPa, the structure of DNTF changes suddenly. The variation trend of C₁₁, C₂₂ and C₃₃ values is consistent with that of pressure. In addition, pressure can improve the compressibility and shear resistance of the DNTF compound. The pressure can reduce the bandgap and further increases the charge density, causing DNTF to decompose and explode.