Mechanical Properties of DO3 Based on First Principles

The elastic constants, ideal strength, band structure and electronic density state of Fe₃Si (DO3) under triaxial tension and triaxial compression were studied using the first principle. The structural parameters calculated at zero pressure are consistent with the experimental results. The dependence of elastic constant and strain can be obtained using static finite strain technique. The ideal triaxial tensile and compressive strength of DO3 were studied by calculating the stress–strain relationship. The micro mechanism that affects the stability of the structure was analyzed using the results of electronic structure calculation. The results showed that the compressive strength of DO3 structure is higher than the tensile strength. When the stress of cell structure exceeds a limit, the covalent bond of Fe–Si is destroyed, resulting in the sudden decrease of G and E and the abnormal change of electronic density of state.