Sand casting rare earth magnesium alloy and preparation method thereof

Abstract

The invention discloses sand casting magnesium-rare earth alloy and a preparation method thereof. The magnesium alloy is prepared from the following components according to mass percent: 8.0 to 14.0wt.% of Gd, 0.01 to 0.85wt.% of Zn, 0.3 to 0.7wt.% of Zr, less than 0.2wt.% of impurity elements including Si, Fe, Cu and Ni and the balance of Mg. Solution treatment is performed on the sand casting magnesium-rare earth alloy obtained by fusion casting at 480 to 530 DEG C for 8 to 16 hours, hardening is performed at 25 to 80 DEG C, and then single-stage aging treatment is performed at 200 to 225 DEG C for 16 to 128 hours, so that the magnesium alloy with good mechanical properties can be obtained. According to the sand casting magnesium-rare earth alloy and the preparation method, a Y element is replaced by a small quantity of Zn elements, so that the oxidation tendency is effectively reduced in the process of alloy fusion casting, and the probability of occurrence of casting defects such as oxide skin is reduced; additionally, a nonbasal slip system is activated during deformation at room temperature, and Mg-Gd-Zn basal precipitated phases are formed, so that the room-temperature ductility of materials is obviously increased in the condition that the alloy strength is not reduced.

Description

technical field [0001] The invention relates to a sand casting rare earth magnesium alloy and a preparation method thereof, belonging to the technical field of metal structural materials. Background technique [0002] As the lightest metal structural material, magnesium alloy has the advantages of high specific strength, high specific stiffness, and good shock absorption, and is widely used in aerospace, transportation, and 3C fields. The Mg-Gd-Y series has been widely used in the aerospace field in recent years due to its good room temperature strength and heat resistance, such as the VW103Z alloy in the 2016 edition of the national standard: Mg-10Gd-3Y-Zr (wt.% )alloy. However, this kind of alloy is easy to form oxide scale in the melting and casting process, and the existence of oxide scale significantly reduces the mechanical properties of VW103Z alloy castings and the yield of forgings, which seriously limits the wide application of Mg-Gd-Y alloy. Such alloys include:...

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Problems solved by technology

This type of scale defect is one of the main reasons for the low yield of Mg-Gd-Y alloy castings and forgings, and it is also the main reason for the low yield of Y-containing magnesium alloys WE43 (Mg-4Y-2Nd-1RE, wt.%), WE54 cast products One of the main reasons for the low

[0003] In addition to the easy formation of scale, the low plasticity of Mg-Gd-Y alloys is another main reason for its limited application.