Morphology and properties of Mg 2 Si and Mg 2 (Si x Sn 1− x ) reinforcements in magnesium alloys

Abstract

In this paper, the effects of Sr, Sb, Sr+Sb and Sn on Mg₂Si reinforcement phases in an Mg–Al–Zn–Si alloy are studied, and the structures and characteristics of Mg₂(Si _x Sn_1−x) phases are analysed with first-principle calculations. The results show that the coarse eutectic Mg₂Si can be refined by modifying processes with Sr, Sb, and their combination. When alloying with Sn, a new reinforcement phase Mg₂(Si _x Sn_1−x) forms by a substitution reaction, instead of Mg₂Si. Calculations indicate that Mg₂(Si _x Sn_1−x) has a certain percentage of covalent bonds, which ensure it has sufficient hardness to act as a reinforcement phase. Calculated results for physical parameters, such as the bulk modulus and shear modulus, indicate that an Mg₂(Si _x Sn_1−x) intermetallic exhibits greater ductility than Mg₂Si.

Highlights

The coarse eutectic Mg₂Si can be refined by modifying processes.

A new phase Mg₂(Si _x Sn_1−x) forms by substitution reaction during solidification.

Mg₂(Si _x Sn_1−x) has certain covalent bound percentage.

Mg₂(Si _x Sn_1−x) has better plasticity than that of Mg₂Si.

Keywords

Mg–Al–Zn–Si alloy first-principle calculation

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