Magnesium alloy and preparation method thereof

Abstract

The invention discloses a magnesium alloy. The magnesium alloy is characterized by comprising, by mass, 7.8-9.2% of Al, 0.2-0.8% of Zn, 0.05-0.4% of Mn, 0.001-0.1% of Y, 0.001-0.1% of Ce, less than orequal to 0.01% of Fe, less than or equal to 0.1% of Si, less than or equal to 0.01% of Cu, less than or equal to 0.01% of Ni, and the balance Mg and inevitable impurities. Trace rare earth elements of yttrium and cerium are added in an AZ80 magnesium alloy to refine matrix grains; and when the magnesium alloy is solidified, Ce and Y atoms are easily enriched at a solid-liquid phase interface, sothat the concentration of solute atoms in a liquid phase is increased, the increment of the amount of precipitation of a second phase is facilitated, the gathering of a network-shaped beta phase in agrain boundary is reduced, and the corrosion resistance is improved when the strength satisfies the performance requirements.

Description

technical field [0001] The invention belongs to the field of metals, and in particular relates to a magnesium alloy and a preparation method thereof. Background technique [0002] Magnesium alloy is currently the lightest metal structure material, which has been widely used in automobiles, aerospace, rail transit and other fields. It has high specific strength, specific stiffness, excellent damping performance, antimagnetic, shielding, heat dissipation, easy cutting, It has many advantages such as easy recycling, but the corrosion resistance of magnesium alloy is weak, which seriously limits its application. [0003] AZ80 magnesium alloy is a widely used structural magnesium alloy material, which has good mechanical properties and relatively low manufacturing cost. In the as-cast state, the grains of AZ80 magnesium alloy are relatively coarse, the β phase forms a network at the grain boundary, and the strength and toughness of the alloy are low. After the alloy undergoes t...

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Problems solved by technology

Most of the β phases at the grain boundaries are integrated into the matrix after homogenization treatment. During the aging treatment process after thermal deformation, the supersaturated solid solution directly precipitates the discontinuous β phase with high stability, which further improves the strength of the AZ80 alloy, but Because in the as-cast state, the β phase gathers in a large amount at the grain boundary to form a network, and the subsequent thermoplastic deformation still has the β phase agglomeration, resulting in uneven dispersion of the β phase after aging, resulting in uneven mechanical properties

Moreover, the existing AZ80 magnesium alloy has fewer grain nucleation base points, resulting in coarse grains, and coarse grains will also cause uneven mechanical properties.

[0004] Magnesium alloys have poor corrosion resistance. Compared with other metal materials, magnesium and its alloys have more active chemical properties, strong chemical and electrochemical activities, and their standard electrode potential is low (-2.37V). The formed oxide film is usually loose and porous, which cannot prevent the further oxidation of the matrix alloy by the outside world, so in a humid environment and Cl - Very susceptible to severe corrosion in the presence of

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