Cast magnesium alloy of low linear shrinkage

Abstract

The invention discloses a cast magnesium alloy of low linear shrinkage, which belongs to the field of magnesium alloys. The magnesium alloy consists of Mg, Al, Zn, Mn, rare earth, Nb, Li and M element, wherein the materials have the following weight percentage composition: 1.5-25 percent of Al, 0.1-3.5 percent of Zn, 0.1-2.2 percent of Mn, 0.0002-16 percent of rare earth, 0.0002-4 percent of Nb, 0.0002-9 percent of Li, 0.0002-2 percent of M element and the balance Mg; and the M element is at least one of Zr, Ti, Sr, Ca, C and B. According to the heat-resistant magnesium alloy, the rare earth element and the Nb element are added into the magnesium alloy, so that the structure of beta phase is changed; the Zr element and the M element are added to refine crystal grains; due to combined action of the elements, latent heat of crystallization during alloy solidification is changed; and the magnesium alloy which has superior mold-filling capacity, low shrinkage, superior mechanical property and good machinability, fluidity and die-cast performance and is suitable for casting is obtained.

Description

technical field [0001] The invention relates to a magnesium alloy, in particular to a high-performance magnesium alloy suitable for casting, especially for high-pressure die-casting. Background technique [0002] With the development of science and technology, vehicles represented by automobiles need to further develop new products with higher fuel efficiency by reducing the weight of the body. In the automobile manufacturing industry, magnesium alloy, as a new type of lightweight metal material, is used by automobile manufacturers to replace traditional cast iron in order to achieve the purpose of reducing the weight of the vehicle body. [0003] At present, the grades of domestic MgAlZn series die-casting magnesium alloys are YM302, YM303, YM304, YM305; the grades of MgAlZn series die-casting magnesium alloys of the American standard ASTM B are AZ91A, AZ91B, AZ91D; the grades of MgAlZn series die-casting magnesium alloys of the Japanese standard JIS H are MDC1B, MDC1D; Eu...

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Problems solved by technology

[0004] In the process of realizing the present invention, the inventors found that the prior art has at least the following problems: when casting magnesium alloys, the molten metal is affected by volume or linear shrinkage during the process of solidification, and the internal stress is very large, which is easy to cause Internal shrinkage and surface cracking of the casting, and even the phenomenon that the casting will break when the mold is opened

This hot cracking phenomenon seriously affects the application of cast magnesium alloys and affects the pass rate of magnesium alloy parts

The shrinkage rate of the above-mentioned die-casting magnesium alloy wire is 1.5-2%, and there is obvious thermal cracking phenomenon, which limits its application range

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