Based on the first-principles method of density function theory,the crystal structure stability,electronic properties,elastic constants and phono properties of the main strengthening phase Mg2Si,Al2Ca and Mg2Ca in Mg-Al-Ca-Si alloy were studied.The calculated lattice constants are in good agreement with the experimental data and literature values.The calculation results of alloy forming energy and binding energy show that Al2Ca has the strongest alloy forming ability and stability.The bulk modulus,shear modulus,youngs modulus and poissons ratio of Al2Ca,Mg2Ca and Mg2Si were calculated.The results show that the three binary phases are brittle phases;the structural stability mechanism is analyzed by calculation of electron density of states,Mulliken electron occupation number and metallicity.It shows that the order of covalent bond strength is Al2Ca,Mg2Si and Mg2Ca.The phonon properties show that the lattice vibrations of Al2Ca,Mg2Ca and Mg2Si are strong near 5.65,5.93 and 6.53 THz,respectively.
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