阅读说明：本技术 一种利用脉冲电流快速消除稀土镁合金中元素偏析的方法 (Method for rapidly eliminating element segregation in rare earth magnesium alloy by using pulse current ) 是由 张新房 冯莹 于 2021-08-18 设计创作，主要内容包括：本发明实施例公开一种利用脉冲电流快速消除稀土镁合金中元素偏析的方法,属于稀土镁合金均质化精炼的技术领域。所述方法具体包括如下步骤：S1：对以稀土元素钆(Gd)为主要合金元素的稀土镁合金进行熔炼；S2：确定脉冲电流处理参数；S3：脉冲电流处理；S4：对脉冲电流处理后的稀土镁合金不同位置进行SEM扫描电镜观察,获得不同位置稀土元素的偏析情况。与未进行均质化的稀土镁合金相比,本发明能在短时间内大幅提高稀土镁合金的各项性能,增加稀土的利用率。与其他均质化方式相比,本发明处理时间短,设备简单,效果更佳,不需其他方式辅助,可独立作用达到均匀化效果,但也可与其他方式共同作用,互不影响,降低工业化转化的成本。(The embodiment of the invention discloses a method for rapidly eliminating element segregation in rare earth magnesium alloy by using pulse current, belonging to the technical field of rare earth magnesium alloy homogenizing and refining. The method specifically comprises the following steps: s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element; s2: determining a pulse current processing parameter; s3: pulse current processing; s4: and carrying out SEM scanning electron microscope observation on different positions of the rare earth magnesium alloy after the pulse current treatment to obtain the segregation conditions of the rare earth elements at different positions. Compared with the rare earth magnesium alloy which is not homogenized, the method can greatly improve various properties of the rare earth magnesium alloy in a short time and increase the utilization rate of the rare earth. Compared with other homogenization methods, the method has the advantages of short treatment time, simple equipment and better effect, does not need other auxiliary methods, can independently act to achieve the homogenization effect, can also act together with other methods without mutual influence, and reduces the cost of industrial conversion.)

1. A method for rapidly eliminating element segregation in rare earth magnesium alloy by using pulse current is characterized by comprising the following steps:

s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element;

s2: determining a pulse current processing parameter;

s3: pulse current processing;

s4: and carrying out SEM scanning electron microscope observation on different positions of the rare earth magnesium alloy after the pulse current treatment to obtain the segregation conditions of the rare earth elements at different positions.

2. The method for rapidly eliminating the element segregation in the rare earth magnesium alloy by using the pulse current as claimed in claim 1, wherein the parameter ranges of the pulse current treatment in the step S2 are as follows: frequency is 10-50000Hz, pulse width is 1-1000 mus, current is 20-5000A, and action time is 5-60 min.

3. The method for rapidly eliminating element segregation in rare earth magnesium alloy according to claim 1, wherein the melting in step S1 is performed in an anti-oxidation environment.

4. The method for rapidly eliminating element segregation in rare earth magnesium alloy according to claim 3, wherein the oxidation-preventing environment in step S1 includes protective atmosphere or addition of covering agent.

5. The method as claimed in claim 4, wherein the melting in step S1 is performed by controlling the first temperature-rise rate 175-.

6. The method for rapidly eliminating element segregation in rare earth magnesium alloy according to claim 1, wherein the pulse current processing parameters in the step S2 are selected according to the crucible size and the type characteristics of the rare earth magnesium alloy.

7. The method for rapidly eliminating element segregation in rare earth magnesium alloy according to claim 6, wherein the parameters of the pulse current treatment in step S2 are selected as follows: the crucible is a corundum crucible with the size of phi 37 multiplied by 62mm, the electrodes are two steel electrodes with the size of 300 multiplied by 10 multiplied by 1mm, the electrodes are inserted into the melt for 2.8-3.2mm, the parameters of the pulse current are selected to be 31000Hz, 30 mus and 80A, and the action time is 8-12 min; the crucible is a corundum crucible with the size of phi 37 multiplied by 62mm, the electrodes are two steel electrodes with the size of 300 multiplied by 10 multiplied by 1mm, the electrodes are inserted into the melt for 2.8-3.2mm, the parameters of the pulse current are selected to be 31000Hz, 30 mus and 60A, and the action time is 12-18 min; selecting proper pulse current processing parameters according to the size of the crucible and the type characteristics of the rare earth magnesium alloy: the crucible is a corundum crucible with the size of phi 37 multiplied by 62mm, the electrodes are two steel electrodes with the size of 300 multiplied by 10 multiplied by 1mm, the electrodes are inserted into the melt by 8-12mm, the pulse current parameters are 31000Hz, 30 mu s and 80A, and the action time is 4-7 min; the crucible is a corundum crucible with the size of phi 37 multiplied by 62mm, the electrodes are two steel electrodes with the size of 300 multiplied by 10 multiplied by 1mm, the electrodes are inserted into the melt by 8-12mm, the parameters of the pulse current are selected to be 31000Hz, 30 mu s and 80A, and the action time is 13-18 min.

8. The method for rapidly eliminating the element segregation in the rare earth magnesium alloy by using the pulse current as claimed in claim 6, wherein in the industrial production practice, the pulse current processing parameters in the step S2 are selected as follows: a smelting furnace with the grade of 500-600kg, electrodes are inserted into the melt for 48-52mm, the parameters of pulse current are selected to be 10-50000Hz, 10-1000 mus, 100-5000A, the treatment is started when the magnesium alloy is molten, and the treatment is stopped when the magnesium alloy is cooled to 380-420 ℃, and the process is carried out for 50-60 min.

9. The method for rapidly eliminating element segregation in rare earth magnesium alloy according to claim 1, wherein the pulsed current treatment in step S3 comprises: inserting and fixing an electrode, setting corresponding pulse current processing parameters, and starting to load pulse current; and after the pulse current is loaded for a fixed time, closing the pulse current equipment.

10. The method for rapidly eliminating element segregation in rare earth magnesium alloy according to claim 1, wherein the element segregation in the rare earth magnesium alloy treated by the method is reduced by 70-90% compared with the magnesium alloy without pulse treatment.

Technical Field

The invention belongs to the technical field of rare earth magnesium alloy homogenizing refining, and relates to a method for rapidly eliminating element segregation in a rare earth magnesium alloy by using pulse current.

Background

The continuous development of the aerospace industry makes the demand for high-performance materials more urgent, and the magnesium alloy as the lightest structural metal material in practical engineering application has the advantages of small density, high specific strength and specific stiffness, excellent damping performance and the like, and is very suitable for being applied to the fields of aerospace and the like with high requirements on material lightweight.

However, the common magnesium alloy has poor corrosion resistance and high temperature performance, and the application range is very limited. The rare earth magnesium alloy is widely applied to the aerospace field, such as aviation seats on airplanes, engine housings, and housings, supports, shaft sleeves, beams of satellites, and the like, by virtue of the improvement of corrosion resistance and high-temperature mechanical properties. The continuous optimization of the rare earth magnesium alloy is one of the future focus problems in the aerospace field.

Among all rare earth elements, gadolinium (Gd) is widely considered to be an element that is most suitable for use in magnesium alloys to improve the performance thereof, because of its highest solid solubility in magnesium and various strengthening effects such as solid solution strengthening, aging strengthening, precipitation strengthening and the like on magnesium alloys.

The characteristics of high-temperature high solid solubility and low-temperature low solid solubility of gadolinium (Gd) rare earth elements in metals can enhance the precipitation strengthening effect of the rare earth elements in magnesium alloys. On the other hand, the low solid solubility of gadolinium (Gd) in the temperature range of the magnesium alloy solidification process can make the rare earth magnesium alloy have coarse grains, serious element segregation, failure of solid solution strengthening and high rare earth loss rate, so that the rare earth magnesium alloy is extremely easy to crack and cannot be rolled under the combined action of the elements, and the improvement of the magnesium alloy performance is very limited. Therefore, the homogenizing smelting of the rare earth magnesium alloy becomes a key problem for the continuous development of the rare earth magnesium alloy.

In the prior art, many scholars have tried the homogenization treatment of rare earth magnesium alloy, including the following methods:

1) electrolytic treatment

For example: patent CN112030193A discloses a method for reducing segregation of gadolinium-yttrium-magnesium-alloy, and the inventor successfully smelts rare earth-magnesium alloy with lower segregation degree by carrying out electrolytic preparation on rare earth-magnesium alloy. Although the rare earth magnesium alloy prepared by the method has small segregation degree, the method is difficult to be widely applied in industrial practice due to the factors of complicated equipment, complicated process, precious initial materials and the like.

2) Multiple refining mode co-processing

For example: the patent CN1060115771A discloses a preparation method for reducing zirconium compound segregation of a ZK61M zirconium-containing magnesium alloy ingot, which successfully reduces zirconium compound segregation of the magnesium alloy ingot through the processes of flaring device smelting, argon refining, stirring refining and powder spraying refining. On one hand, the mode adopts the composite action of a plurality of refining methods, and has long flow and more devices; on the other hand, whether the method can be effectively applied to rare earth elements with properties greatly different from those of Zr still needs to be researched.

3) Low frequency electromagnetic field treatment

For example: patent CN103849801A discloses a method for preparing a high-strength heat-resistant magnesium alloy ingot blank by electromagnetic semi-continuous casting, which greatly reduces the macrosegregation of rare earth magnesium alloy by applying a low-frequency electromagnetic field in the process of flowing melt into a crystallizer, thereby obtaining the method for semi-continuously casting the rare earth magnesium alloy. However, the requirement for equipment is high, a mold equipped with an excitation coil is required, and the problem of micro segregation is still unsolved.

4) Slag stirring and crushing treatment

For example: patent CN212167288A discloses a strong stirring device for refining magnesium and aluminum alloy grains, which fully crushes and refines part of slag remaining in molten metal, plays a role in refining grains, and reduces component segregation. However, the disadvantages are obvious, the removal of inclusions in the magnesium alloy is hindered, the magnesium melt is very easy to react with air, and the device can aggravate the reaction, increase the loss of magnesium and increase more safety hazards. The magnesium-gadolinium alloy has small effect in rare earth magnesium alloys with large solid solubility along with temperature change.

5) Coupling treatment of pulse current and joule heat

For example: patent CN111575619B provides a method for rapidly eliminating dendritic segregation in nickel-based wrought superalloy cast ingots for turbine disks by pulse current, and the diffusion capability of segregation element atoms is enhanced through the coupling effect of the pulse current and joule heat, so that rapid elimination of dendritic segregation under an external field of the pulse current is realized. The method belongs to the field of electromagnetic heating treatment, the material is a deformed high-temperature alloy semi-finished product which is subjected to first-stage homogenization treatment (aiming at eliminating interdendritic Laves phases), namely, is subjected to second-stage homogenization treatment (aiming at eliminating interdendritic element segregation), and the pulse current passes through the deformed high-temperature alloy semi-finished product and is a solid material.

In summary, the prior art does not provide a method for eliminating the segregation of gadolinium (Gd) element in grain boundaries of a rare earth magnesium alloy using gadolinium as a main alloy element by using a pulse current, the 5 treatment methods are not suitable for eliminating the segregation of gadolinium (Gd) element in grain boundaries, more than 30% of grain boundary regions are gadolinium-rich regions formed by the segregation, and the content of gadolinium in the grains is very low, so that the grains of a magnesium alloy finished product are coarse, the plasticity is seriously reduced, the content of rare earth elements dissolved in the grains is too low, the corrosion resistance of the whole magnesium alloy cannot be greatly improved, meanwhile, the precipitated second phase cannot be uniformly distributed, so that the precipitation strengthening effect is greatly reduced, and the strength of the material cannot achieve an ideal effect. Other purposes and technical effects such as the pulse current treatment also do not relate to the foregoing, and particularly how to rapidly eliminate the element segregation in the rare earth magnesium alloy through the pulse current is not considered.

Disclosure of Invention

The invention solves the technical problem that the existing rare earth magnesium alloy homogenization treatment method is not suitable for eliminating the segregation of gadolinium (Gd) element of rare earth magnesium alloy taking gadolinium (Gd) as a main alloy element at the grain boundary, has the defects of complex treatment process, high cost, high operation difficulty, influence on other refining procedures, insufficient environmental protection and the like, and can not completely solve the problem of rare earth magnesium alloy homogenization refining.

In order to solve the technical problems, the invention provides the following technical scheme:

a method for rapidly eliminating element segregation in rare earth magnesium alloy by using pulse current specifically comprises the following steps:

s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element;

s2: determining a pulse current processing parameter;

s3: pulse current processing;

s4: and carrying out SEM scanning electron microscope observation on different positions of the rare earth magnesium alloy after the pulse current treatment to obtain the segregation conditions of the rare earth elements at different positions.

Preferably, the parameter range of the pulse current processing in step S2 is: frequency is 10-50000Hz, pulse width is 1-1000 mus, current is 20-5000A, and action time is 5-60 min.

Preferably, the smelting in the step S1 needs to be performed in an oxidation-proof environment.

Preferably, the oxidation preventing environment in step S1 includes a protective atmosphere or an addition of a covering agent.

Preferably, the smelting in the step S1 is to raise the smelting temperature to 760-.

Preferably, the parameters of the pulse current processing in the step S2 are selected according to the size of the crucible and the type characteristics of the rare earth magnesium alloy.

Preferably, the pulse current processing parameters in step S2 are selected as: the crucible is a corundum crucible with the size of phi 37 multiplied by 62mm, the electrodes are two steel electrodes with the size of 300 multiplied by 10 multiplied by 1mm, the electrodes are inserted into the melt for 2.8-3.2mm, the parameters of the pulse current are selected to be 31000Hz, 30 mus and 80A, and the action time is 8-12 min; the crucible is a corundum crucible with the size of phi 37 multiplied by 62mm, the electrodes are two steel electrodes with the size of 300 multiplied by 10 multiplied by 1mm, the electrodes are inserted into the melt for 2.8-3.2mm, the parameters of the pulse current are selected to be 31000Hz, 30 mus and 60A, and the action time is 12-18 min; selecting proper pulse current processing parameters according to the size of the crucible and the type characteristics of the rare earth magnesium alloy: the crucible is a corundum crucible with the size of phi 37 multiplied by 62mm, the electrodes are two steel electrodes with the size of 300 multiplied by 10 multiplied by 1mm, the electrodes are inserted into the melt by 8-12mm, the pulse current parameters are 31000Hz, 30 mu s and 80A, and the action time is 4-7 min; the crucible is a corundum crucible with the size of phi 37 multiplied by 62mm, the electrodes are two steel electrodes with the size of 300 multiplied by 10 multiplied by 1mm, the electrodes are inserted into the melt by 8-12mm, the parameters of the pulse current are selected to be 31000Hz, 30 mu s and 80A, and the action time is 13-18 min.

Preferably, in the industrial practice, the parameters of the pulse current processing in step S2 are selected as follows: a smelting furnace with the grade of 500-600kg, electrodes are inserted into the melt for 48-52mm, the parameters of pulse current are selected to be 10-50000Hz, 10-1000 mus, 100-5000A, the treatment is started when the magnesium alloy is molten, and the treatment is stopped when the magnesium alloy is cooled to 380-420 ℃, and the process is carried out for 50-60 min.

Preferably, the pulse current processing in step S3 includes: inserting and fixing an electrode, setting corresponding pulse current processing parameters, and starting to load pulse current; and after the pulse current is loaded for a fixed time, closing the pulse current equipment.

Preferably, the element segregation in the rare earth magnesium alloy treated by the method is reduced by 70-90% compared with the magnesium alloy without pulse treatment.

The principle of eliminating the segregation of gadolinium (Gd) element of rare earth magnesium alloy taking gadolinium (Gd) as a main alloy element at grain boundary by using pulse current is as follows:

the invention selects YFZM-0 type magnesium alloy (Gd content is 10% +), when refined by the traditional standing method, more than 30% of grain boundary regions are Gd-rich regions formed by segregation, the Gd content in crystal is very low and is far lower than the maximum solid solubility, which can cause that the crystal grains of the magnesium alloy finished product are coarse, the plasticity is seriously reduced, the content of rare earth elements dissolved in the crystal is too low, the integral corrosion resistance of the magnesium alloy can not be greatly improved, meanwhile, the precipitated second phase can not be uniformly distributed, so that the precipitation strengthening effect is greatly reduced, and the strength of the material can not achieve the ideal effect. Therefore, in order to obtain a higher-quality rare earth magnesium alloy, the rare earth magnesium alloy must be subjected to homogenizing refining, the segregation of rare earth elements is inhibited, the solid solution strengthening effect is enhanced, the crystal grains are refined, the second phase is dispersed and distributed, and the rare earth magnesium alloy with excellent corrosion resistance, high-temperature creep resistance, high-temperature mechanical property and the like is obtained under the dual actions of precipitation strengthening and solid solution strengthening, so that the further development of the aerospace industry is promoted.

The rare earth elements are uniformly distributed in the magnesium alloy through pulse current treatment, the segregation of the rare earth elements in crystal boundaries is inhibited, solid solution strengthening and precipitation strengthening can play a role to the maximum extent, and the rare earth magnesium alloy with excellent corrosion resistance, high-temperature creep resistance, high-temperature mechanical property and the like is obtained.

The technical scheme provided by the embodiment of the invention at least has the following beneficial effects:

compared with the rare earth magnesium alloy which is not homogenized, the scheme can greatly improve various performances of the rare earth magnesium alloy in a short time and increase the utilization rate of the rare earth. Compared with other homogenization modes, the scheme has the advantages of short treatment time, simple equipment and better effect, does not need other auxiliary modes, can independently act to achieve the homogenization effect, but can also act together with other modes without mutual influence, and greatly reduces the cost of industrial conversion.

Therefore, the scheme adopts pulse current, consumes little energy, can greatly reduce energy consumption and meets the requirement of the current industrial green development planning.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is an SEM image showing segregation of rare earth elements at different parts of a rare earth magnesium alloy in a conventional refining method without pulse current intervention and by a method for rapidly eliminating segregation of elements in the rare earth magnesium alloy by using pulse current in example 1 of the present invention;

wherein: a. c and e are respectively SEM images of rare earth element segregation conditions at the top, the middle and the bottom of the rare earth magnesium alloy treated by the traditional refining mode, and b, d and f are respectively SEM images of rare earth element segregation conditions at the top, the middle and the bottom of the rare earth magnesium alloy subjected to the pulse current rapid elimination treatment in the embodiment 1.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

Example 1:

in this example, the rare earth magnesium alloy was subjected to pulse current treatment. The method comprises the following specific steps:

s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element. And (3) putting the dried magnesium alloy into a crucible, adding an RJ-2 covering agent, and heating the crucible to 760 ℃ by slowly heating (180 ℃/h) and rapidly heating (280 ℃/h) for 3 h.

S2: pulse current processing parameters are determined. Setting the pulse current processing parameter range, determining the pulse current parameters of 31000Hz, 30 mus and 80A, and the action time of 10 min.

S3: and (5) pulse current processing. Symmetrically inserting the prepared steel electrodes into two sides of the crucible, and confirming that the electrodes are inserted into the melt by 3 mm; and connecting a pulse current generator to perform 10min pulse current processing.

S4: SEM scanning electron microscope observation is carried out on different positions of the magnesium alloy after the pulse current treatment, and the segregation conditions of the rare earth elements at different positions are observed, as shown in figure 1, b, d and f are respectively SEM pictures of the segregation conditions of the rare earth elements at the top, the middle and the bottom of the rare earth magnesium alloy after the pulse current rapid elimination treatment in the embodiment 1.

Example 2:

in this example, the rare earth magnesium alloy was subjected to pulse current treatment. The method comprises the following specific steps:

s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element. And (3) putting the dried magnesium alloy into a crucible, adding an RJ-2 covering agent, and heating the crucible to 760 ℃ by slowly heating (180 ℃/h) and rapidly heating (280 ℃/h) for 3 h.

S2: pulse current processing parameters are determined. The parameter range of the pulse current is set, the pulse current parameter is determined to be 31000Hz, 30 mus and 60A, and the action time is 15 min.

S3: and (5) pulse current processing. Symmetrically inserting the prepared steel electrodes into two sides of the crucible, and confirming that the electrodes are inserted into the melt by 3 mm; and connecting a pulse current generator to perform 15min pulse current processing.

S4: and (4) carrying out SEM (scanning electron microscope) observation on different positions of the magnesium alloy treated by the pulse current, and observing the segregation conditions of the rare earth elements at different positions.

Example 3:

in this example, the rare earth magnesium alloy was subjected to pulse current treatment. The method comprises the following specific steps:

s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element. And (3) putting the dried magnesium alloy into a crucible, adding an RJ-2 covering agent, and heating the crucible to 760 ℃ by slowly heating (180 ℃/h) and rapidly heating (280 ℃/h) for 3 h.

S2: pulse current processing parameters are determined. The parameter range of the pulse current is set, the pulse current parameters are determined to be 31000Hz, 30 mus and 80A, and the action time is 5 min.

S3: and (5) pulse current processing. Symmetrically inserting the prepared steel electrodes into two sides of the crucible, and confirming that the electrodes are inserted into the melt by 10 mm; and connecting a pulse current generator to perform 5min pulse current processing.

S4: and (4) carrying out SEM (scanning electron microscope) observation on different positions of the magnesium alloy treated by the pulse current, and observing the segregation conditions of the rare earth elements at different positions.

Example 4:

in this example, the rare earth magnesium alloy was subjected to pulse current treatment. The method comprises the following specific steps:

s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element. And (3) putting the dried magnesium alloy into a crucible, adding an RJ-2 covering agent, and heating the crucible to 760 ℃ by slowly heating (180 ℃/h) and rapidly heating (280 ℃/h) for 3 h.

S2: pulse current processing parameters are determined. The parameter range of the pulse current is set, the pulse current parameters are determined to be 31000Hz, 30 mus and 80A, and the action time is 15 min.

S3: and (5) pulse current processing. Symmetrically inserting the prepared steel electrodes into two sides of the crucible, and confirming that the electrodes are inserted into the melt by 10 mm; and connecting a pulse current generator to perform 15min pulse current processing.

S4: and (4) carrying out SEM (scanning electron microscope) observation on different positions of the magnesium alloy treated by the pulse current, and observing the segregation conditions of the rare earth elements at different positions.

Example 5:

the embodiment carries out pulse current treatment on the rare earth magnesium alloy, and is suitable for the magnesium alloy of industrial production level. The method comprises the following specific steps:

s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element. The raw materials are put into a smelting furnace, a covering agent is added, and the temperature is raised to be higher than the melting point.

S2: pulse current processing parameters are determined. Setting the parameter range of the pulse current, determining the pulse current parameter to be 50000Hz, 10 mus and 1000A, and acting on the magnesium alloy in the stage from the molten state to the solidification to 400 ℃.

S3: and (5) pulse current processing. Symmetrically inserting the prepared steel electrodes into two sides of the crucible, and confirming that the electrodes are inserted into the melt by 50 mm; and connecting a pulse current generator to perform pulse current processing.

S4: and (3) cooling the magnesium alloy in the pulse current heating state in the furnace, and turning off the pulse current generator when the temperature reaches 400 ℃.

S5: and (4) carrying out SEM (scanning electron microscope) observation on different positions of the magnesium alloy treated by the pulse current, and observing the segregation conditions of the rare earth elements at different positions.

Comparative example:

s1: smelting rare earth magnesium alloy with rare earth element gadolinium (Gd) as a main alloy element. And (3) putting the dried magnesium alloy into a crucible, adding an RJ-2 covering agent, and heating the crucible to 760 ℃ by slowly heating (180 ℃/h) and rapidly heating (280 ℃/h) for 3 h.

S2: refining modes and parameters are determined. Refining by standing and settling method, and keeping the temperature at 760 deg.C for 10 min.

S3: keeping the temperature at 760 ℃ for 10min, taking out the crucible and cooling in air.

S4: SEM scanning electron microscope observation is carried out on different positions of the magnesium alloy without pulse treatment, and the segregation conditions of rare earth elements at different positions are observed. As shown in fig. 1, a, c, e are SEM images of rare earth element segregation at the top, middle, and bottom of the rare earth magnesium alloy treated by the conventional refining method, respectively.

Therefore, as shown in FIG. 1, comparing SEM images of rare earth element segregation of a and b, c and d, and e and f, respectively, it can be seen that the element segregation in the rare earth magnesium alloy treated by the method is reduced by 70-90% compared with that in the magnesium alloy without pulse treatment.

Compared with the rare earth magnesium alloy which is not homogenized, the scheme can greatly improve various performances of the rare earth magnesium alloy in a short time and increase the utilization rate of the rare earth. Compared with other homogenization modes, the scheme has the advantages of short treatment time, simple equipment and better effect, does not need other auxiliary modes, can independently act to achieve the homogenization effect, but can also act together with other modes without mutual influence, and greatly reduces the cost of industrial conversion.

Therefore, the scheme adopts pulse current, consumes little energy, can greatly reduce energy consumption and meets the requirement of the current industrial green development planning.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.