Grain refiner for mg-al magnesium alloy and preparation method thereof

Abstract

The invention discloses a grain refiner for magnesium-aluminum (Mg-Al) magnesium alloy and a preparation method thereof. The grain refiner consists of a calcium magnesium stannum (CaMgSn) intermediate compound and magnesium, wherein the weight content of impurities is less than or equal to 0.3 percent; and the CaMgSn intermediate compound with small granularity is used as a heterogeneous nucleation core of a substrate in solidification, the formed crystal particle is fine, the addition quantity is stable, and the crystal particle is high efficient to refine and stable. The refiner is prepared in a vacuum induction furnace according to a reasonable formula, the burning of elements can be effectively avoided, the controllability of components is strong, CaMgSn can be dispersed and distributed in the substrate through squeezing, the size is fine, and the refining capacity is further improved. In addition, The AZ31 aluminum-magnesium alloy crystal particle is refined according to the formula and process disclosed by the invention, the size of the cast crystal particle of the magnesium alloy is 70 micrometers, and the crystal particle refining effect is remarkable compared with the size 170 micrometers of the crystal particle of the magnesium alloy without the crystal particle refiner under the same state.

Description

technical field

[0001] The invention relates to the technical field of production and processing of alloy materials, in particular to a grain refiner for AZ31 magnesium alloy, a preparation method of the refiner and a method for preparing a fine-grain magnesium alloy using the refiner. Background technique

[0002] AZ31 magnesium alloy is one of the most commonly used magnesium alloys. It has high specific strength, specific stiffness, excellent casting performance and machining performance, but its strength and toughness are poor. By Hall-patch (σ=σ 0 +Kd -1 / 2 ) shows that for magnesium alloys with larger K values, grain refinement is an effective method for alloy strengthening and toughening.

[0003] Currently, the grain refinement of magnesium alloys is mainly achieved by adding alloying elements. In aluminum-free magnesium alloys, the most effective grain refiner is zirconium; however, zirconium cannot be used in aluminum-containing magnesium alloys because zirconium...

Examples

Embodiment 1

[0039] The grain refiner for Mg-Al series magnesium alloy of this embodiment is composed of CaMgSn intermediate compound and Mg, wherein the weight content of impurities (Mn, Fe, Si, Ni and Cu) is ≤0.3%.

[0040] Prepare the grain refiner for the Mg-Al series magnesium alloy according to the following steps:

[0041] a) According to the formula of the components Ca 0.6%, Sn 1.9%, and the balance Mg, take Ca and Mg and put them into a vacuum induction furnace with an inert gas. The addition of element Ca is realized by adding Mg-20Ca master alloy, Heat to 720°C, keep warm until the loaded material is completely melted, and stir evenly, then add Sn according to the formula amount, keep warm at 720°C until completely melted, stir evenly to fully react the elements, and obtain an alloy melt;

[0042] b) Clean the iron mold with an inner diameter of 85mm and a height of 350mm, and preheat it to 300°C and keep it warm for 10 minutes to make the temperature of the entire mold uniform...

Embodiment 2

[0060] Prepare the grain refiner for the Mg-Al series magnesium alloy according to the following steps:

[0061] a) According to the formula of the components Ca 0.3%, Sn 0.95%, and the balance Mg, the Ca and Mg are loaded into a vacuum induction furnace with an inert gas, and the addition of the element Ca is realized by adding the Mg-20Ca master alloy, Heat to 720°C, keep warm until the loaded material is completely melted, and stir evenly, then add Sn according to the formula amount, keep warm at 720°C until completely melted, stir evenly to fully react the elements, and obtain an alloy melt;

[0062] b) Clean the iron mold with an inner diameter of 85mm and a height of 350mm, and preheat it to 300°C and keep it warm for 10 minutes to make the temperature of the entire mold uniform. Then, the alloy melt, which was completely melted, stirred and kept warm for 30 minutes, was cast into the preheated iron film under the protection of argon. After being completely solidified, ...

Embodiment 3

[0076] Prepare the grain refiner for the Mg-Al series magnesium alloy according to the following steps:

[0077] a) Take Ca and Mg according to the formula of element weight percentage components Ca3%, Sn9.5%, surplus Mg and pack into a vacuum induction furnace with an inert gas, the addition of element Ca is realized by adding Mg-20Ca master alloy, Heat to 720°C, keep warm until the loaded material is completely melted, and stir evenly, then add Sn according to the formula amount, keep warm at 720°C until completely melted, stir evenly to fully react the elements, and obtain an alloy melt;

[0078] b) Clean the iron mold with an inner diameter of 85mm and a height of 350mm, and preheat it to 300°C and keep it warm for 10 minutes to make the temperature of the entire mold uniform. Then, the alloy melt, which was completely melted, stirred and kept warm for 30 minutes, was cast into the preheated iron film under the protection of argon. After being completely solidified, the m...

technical field

[0001] The invention relates to the technical field of production and processing of alloy materials, in particular to a grain refiner for AZ31 magnesium alloy, a preparation method of the refiner and a method for preparing a fine-grain magnesium alloy using the refiner. Background technique

[0002] AZ31 magnesium alloy is one of the most commonly used magnesium alloys. It has high specific strength, specific stiffness, excellent casting performance and machining performance, but its strength and toughness are poor. By Hall-patch (σ=σ 0 +Kd -1 / 2 ) shows that for magnesium alloys with larger K values, grain refinement is an effective method for alloy strengthening and toughening.

[0003] Currently, the grain refinement of magnesium alloys is mainly achieved by adding alloying elements. In aluminum-free magnesium alloys, the most effective grain refiner is zirconium; however, zirconium cannot be used in aluminum-containing magnesium alloys because zirconium...

Examples

Embodiment 1

[0039] The grain refiner for Mg-Al series magnesium alloy of this embodiment is composed of CaMgSn intermediate compound and Mg, wherein the weight content of impurities (Mn, Fe, Si, Ni and Cu) is ≤0.3%.

[0040] Prepare the grain refiner for the Mg-Al series magnesium alloy according to the following steps:

[0041] a) According to the formula of the components Ca 0.6%, Sn 1.9%, and the balance Mg, take Ca and Mg and put them into a vacuum induction furnace with an inert gas. The addition of element Ca is realized by adding Mg-20Ca master alloy, Heat to 720°C, keep warm until the loaded material is completely melted, and stir evenly, then add Sn according to the formula amount, keep warm at 720°C until completely melted, stir evenly to fully react the elements, and obtain an alloy melt;

[0042] b) Clean the iron mold with an inner diameter of 85mm and a height of 350mm, and preheat it to 300°C and keep it warm for 10 minutes to make the temperature of the entire mold uniform...

Embodiment 2

[0060] Prepare the grain refiner for the Mg-Al series magnesium alloy according to the following steps:

[0061] a) According to the formula of the components Ca 0.3%, Sn 0.95%, and the balance Mg, the Ca and Mg are loaded into a vacuum induction furnace with an inert gas, and the addition of the element Ca is realized by adding the Mg-20Ca master alloy, Heat to 720°C, keep warm until the loaded material is completely melted, and stir evenly, then add Sn according to the formula amount, keep warm at 720°C until completely melted, stir evenly to fully react the elements, and obtain an alloy melt;

[0062] b) Clean the iron mold with an inner diameter of 85mm and a height of 350mm, and preheat it to 300°C and keep it warm for 10 minutes to make the temperature of the entire mold uniform. Then, the alloy melt, which was completely melted, stirred and kept warm for 30 minutes, was cast into the preheated iron film under the protection of argon. After being completely solidified, ...

Embodiment 3

[0076] Prepare the grain refiner for the Mg-Al series magnesium alloy according to the following steps:

[0077] a) Take Ca and Mg according to the formula of element weight percentage components Ca3%, Sn9.5%, surplus Mg and pack into a vacuum induction furnace with an inert gas, the addition of element Ca is realized by adding Mg-20Ca master alloy, Heat to 720°C, keep warm until the loaded material is completely melted, and stir evenly, then add Sn according to the formula amount, keep warm at 720°C until completely melted, stir evenly to fully react the elements, and obtain an alloy melt;

[0078] b) Clean the iron mold with an inner diameter of 85mm and a height of 350mm, and preheat it to 300°C and keep it warm for 10 minutes to make the temperature of the entire mold uniform. Then, the alloy melt, which was completely melted, stirred and kept warm for 30 minutes, was cast into the preheated iron film under the protection of argon. After being completely solidified, the m...

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