Phase Stability and Mechanical Properties of Al₈Fe₄RE via First-Principle Calculations.

We report on the phase stability, elastic, electronic, and lattice dynamic properties of 17 Al₈Fe₄RE (RE = Sc, Y, La⁻Lu) intermetallic compounds (IMCs) using first-principle calculations. The calculated lattice constants coincided with the experimental results. The calculated enthalpy formation indicated that all the 17 IMCs are stable. The elastic constants and various moduli indicated that Al₈Fe₄RE can be used as a strengthening phase due to its high Young's modulus and shear modulus. The 3D surfaces of Young's modulus for Al₈Fe₄RE showed anisotropic behavior, and the values of hardness for the IMCs were high (about 14 GPa). The phonon spectra showed that only Al₈Fe₄Y had a soft mode, which means the other IMCs are all dynamically stable.