High-toughness single-phase solid solution magnesium rare earth-based alloy at room temperature and preparation method thereof

Abstract

The invention relates to a high-temperature single-phase solid-solution magnesium rare earth base alloy of which the chemical composition is Mg-xRE-y(Zn+Sc)-z(Ag+Zr), wherein x is more than or equal to 0.5 and less than or equal to 3.0, y is more than or equal to 0.1 and less than or equal to 1.5, z is more than or equal to 0.01 and less than or equal to 1.0 (wt%), and rare earth elements comprise Gd, Y, Dy, Er, Tm and Lu. A preparation method mainly comprises the following steps of: adding the raw materials into an automatic temperature-controlled resistance furnace, protecting the raw materials by using a mixed gas of sulfur hexafluoride and argon, smelting the raw materials at the temperature of 680-800 DEG C, pouring the melt in a steel mold at the temperature of 650-770 DEG C, fully preheating the steel mold at the temperature of 500-600 DEG C, insulating the steel mold in a 650-750 DEG C furnace for 30-120 min after pouring, and cooling the steel mold by using water to room temperature. The single-phase solid-solution magnesium rare earth base alloy provided by the invention has small grain size, good ductility, room temperature elongation coefficient exceeding 20%, excellent mechanical properties and processing properties and excellent corrosion resistance.

Description

technical field [0001] The invention relates to a metal material and a preparation method thereof, in particular to a magnesium alloy and a preparation method thereof. Background technique [0002] Magnesium alloy has the advantages of light specific gravity, high specific strength and specific stiffness, good damping and machinability, good thermal conductivity, strong electromagnetic shielding ability, good vibration damping and easy recycling, which meets the weight reduction requirements of aviation, aerospace and modern automobile industries. , energy-saving requirements, known as "21st century green engineering materials". [0003] At present, the wrought magnesium alloys mainly include magnesium-aluminum alloys, magnesium-zinc alloys and magnesium rare earth alloys. Magnesium-aluminum alloys are the most commonly used deformation systems, however, this type of alloy has a strong basal texture, significant asymmetry and a relatively narrow processing temperature rang...

AI Technical Summary

Problems solved by technology

Magnesium-aluminum alloys are the most commonly used deformation systems, however, this type of alloy has a strong basal texture, significant asymmetry and a relatively narrow processing temperature range

Since the eutectic temperature of magnesium-aluminum alloy is 437 ℃, the hot working temperature is usually lower than 350 ℃, so the deformation speed is low and the product production cost is high

On the other hand, if a high temperature is chosen (over 350 °C), the eutectic phase dissolves, leading to alloy hot cracking and reduced surface quality [K.U. Kainer, Magnesium Alloys and Technologies, WILEY-VCH Verlag GmbH, Weiheim, 2003]

Because magnesium-zinc series does not contain aluminum, its structure can be effectively refined by adding Zr. However, this type of alloy is easy to form casting micropores, and the trend of hot cracking is obvious during rolling, which is difficult to weld. Therefore, this type of alloy is used in deformed materials. There are also few applications [H.E. Friedrich, B. L.Mordike, Magnesium Technology, Springer Press, Berlin, 2006]

Compared with the above two, the performance of magnesium rare earth alloys is more prominent, such as WE43 (Mg-4.1Y-2.2Nd-1HRE-0.5Zr) and WE54 (Mg-5.2Y-1.7Nd-1.7HRE-0.4Zr) alloys It has good mechanical properties and thermal stability, but with the increase of the rare earth content, the price of the alloy increases obviously, and more importantly, with the increase of the rare earth content, the amount of the second phase particles increases significantly, the alloy The corrosion resistance performance drops sharply

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