CN115874098A - Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy and preparation method thereof - Google Patents
Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy and preparation method thereof Download PDFInfo
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- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 72
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 65
- 229910000861 Mg alloy Inorganic materials 0.000 title claims abstract description 54
- 238000002360 preparation method Methods 0.000 title description 6
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 67
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- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 abstract description 3
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- 229910018461 Al—Mn Inorganic materials 0.000 description 1
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Abstract
The invention provides a Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy, which comprises the following components: al: 4.5-7.5 wt%, la:1.5 to 3.0wt%, sm:0.5 to 1.0wt%, RE except La/Sm: 0.02 to 0.10wt%, zn:0.6 to 1.0wt%, ca:0.15 to 0.50wt%, mn:0.20 to 0.40wt%, and the balance of magnesium and inevitable impurities. According to the invention, through the composite application of the multiple rare earth elements and the alkaline earth elements, the strength performance of the alloy is improved, and the plasticity is improved; the components are optimized through the type collocation and the specific proportion of the multi-element rare earth components, the effects of improving the nucleation density of the rare earth phase and increasing the precipitation efficiency are realized, the precipitation effect of alloying elements is improved, and the total amount and the proportion of the rare earth added in the alloy are limited and optimized on the premise of ensuring the comprehensive performance of the alloy.
Description
Technical Field
The invention belongs to the technical field of magnesium alloy, and particularly relates to a Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy and a preparation method thereof.
Background
With the technical development in the field of automobile manufacturing, the demand for large-sized lightweight components is increasingly urgent, which puts higher requirements on the strength, plasticity and damping performance of magnesium-based lightweight alloys. The Mg-Al-Mn alloy represented by AM60 is widely used because of its advantages of excellent casting property, good plasticity, good damping property and the like. However, such alloys also have inherent performance disadvantages of low strength and relatively poor flow properties, which limit their further expansion. At present, the application of magnesium alloy in the automobile field is expanded from small parts such as shell covers to large-scale thin-wall complex parts and key bearing systems, the problems are more serious, and in order to solve the defects, rare earth elements are introduced into an alloy system so as to improve the strength and the corrosion resistance of the alloy system on the premise of keeping the excellent plasticity of the alloy system, thereby expanding the application field of the alloy system.
The rare earth elements have good strengthening effect in the magnesium alloy, and a proper amount of the rare earth elements not only keep the plasticity of the Mg-Al alloy, but also improve the strength and the corrosion resistance of the alloy, and the comprehensive performance of the alloy is obviously improved compared with the AZ91/AM60 magnesium alloy. At present, the research on the aspects of the optimization and specific collocation of the components of the mixed rare earth is relatively less in the magnesium alloy field, and the Mg-Al alloy added with the rare earth does not show outstanding mechanical properties.
Disclosure of Invention
In view of the above, the invention aims to provide a Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy and a preparation method thereof.
The invention provides a Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy, which comprises the following components:
Al：4.5～7.5wt％，
La：1.5～3.0wt％，
Sm：0.5～1.0wt％，
RE other than La and Sm: 0.02 to 0.10 weight percent,
Zn：0.6～1.0wt％，
Ca：0.15～0.50wt％，
Mn：0.20～0.40wt％，
the balance being Mg and unavoidable impurities.
Preferably, the components are as follows:
Al：5.5～6.5wt％，
La：2.5～3.0wt％，
Sm：0.8～1.0wt％，
RE except La and Sm: 0.02 to 0.05 weight percent,
Zn：0.8～0.9wt％，
Ca：0.15～0.25wt％，
Mn：0.25～0.30wt％，
the balance being Mg and unavoidable impurities.
Preferably, the mass ratio of La to Sm is (2.8-3.2): 1.
Preferably, the RE except La and Sm is at least one selected from Y, gd.
Preferably, the mass content of the unavoidable impurities is < 0.2%.
The invention provides a preparation method of the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy in the technical scheme, which comprises the following steps:
melting an Mg ingot and an Al ingot, heating for the first time, then sequentially adding an Mg-La intermediate alloy, an Mg-Sm intermediate alloy and an Mg-Mn intermediate alloy, and carrying out first standing after melting to obtain a first melt;
keeping the temperature of the first melt at a second temperature, adding Mg-RE intermediate alloy and Mg-Ca intermediate alloy, melting, and then carrying out second standing to obtain a second melt;
heating the second melt to a third temperature, degassing, adding a flux, refining, cooling to a fourth temperature after the refining is finished, and standing for a third time;
and slagging off the alloy liquid after the third standing, and then casting and forming at a fifth temperature to obtain the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy.
Preferably, the temperature of the primary heating is 700-730 ℃; the first standing time is 25-35 min.
Preferably, the second temperature is 700-730 ℃; and the second standing time is 25-35 min.
Preferably, the third temperature is 730 to 750 ℃; the fourth temperature is 690-700 ℃; and the third standing time is 20-30 min.
Preferably, the fifth temperature is 680 to 700 ℃.
Aiming at the actual requirements in the fields of automobiles, rail transit and the like, the invention solves the technical difficulties of poor mechanical property and difficult compatibility of obdurability of a magnesium alloy chamber by the compound application of the multiple rare earth and the rare earth-alkaline earth element, and effectively improves the mechanical property and the technological adaptability of the material by constructing an alloy system of Mg-Al-RE-AE with optimized components.
According to the rare earth component matching scheme based on the rare earth element multi-element microalloying effect, different rare earth elements can reduce the solid solubility of each other in magnesium alloy, the nucleation density is improved under the condition that the total amount is not changed, and the precipitation efficiency is increased, so that the effects of improving the strength performance and reducing the plasticity loss are achieved. In the invention, the light rare earth La-Sm with low cost and good manufacturability and a specific proportion is selected as a main alloying element, and specific component collocation is formed through the multi-element microalloying effect of a small amount of Y/Gd, so that the precipitation quantity of Al-RE phases is effectively increased, the size of the precipitated phases is reduced, and the dispersion degree of the distribution of the Al-RE phases is improved.
The composite application of RE-AE is limited by the nucleation density of precipitated phases, the Mg-Al/Mg-Al-RE alloy system has no outstanding strengthening effect when the content of rare earth is lower, and fine dispersed Al can be formed by adding a proper amount of alkaline earth elements such as Ca and the like 2 The AE phase supplements the Al-RE phase, prevents the rare earth phase from further growing up through the dispersion nucleation effect of the AE phase, further realizes the effects of refining the microstructure morphology, improving the alloy performance and reducing the rare earth dosage, but on one hand, the Ca element with lower content can not form effective improvement effect, on the other hand, the Ca with too high content can be gathered at the microstructure crystal boundary, the Al phase can be aggregated at the microstructure crystal boundary, and the Al phase can not be obtained by the method 2 The Ca particles also grow rapidly, thereby causing a significant decrease in strength and plasticity of the alloy, and failing to serve as a main strengthening element. Through the composite application of rare earth-alkaline earth elements, various Al-RE and Al-AE strengthening phases in the alloy are regulated and controlled, and the method is an effective technical scheme for improving the mechanical property of the alloy chamber.
After the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy provided by the invention is cast, the tensile strength, yield strength and elongation of gold respectively reach: 240-260 MPa, 175-190 MPa and 4-7 percent, and has outstanding advantages in mechanical property compared with the traditional commercial AZ91/AM60 alloy.
Drawings
FIG. 1 shows the as-cast microstructure morphology of a magnesium alloy prepared in example 3 of the present invention;
FIG. 2 is a distribution analysis of the elements of the microstructure of the magnesium alloy prepared in example 3 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The invention provides a Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy, which comprises the following components:
Al：4.5～7.5wt％，
La：1.5～3.0wt％，
Sm：0.5～1.0wt％，
RE other than La and Sm: 0.02 to 0.10 weight percent,
Zn：0.6～1.0wt％，
Ca：0.15～0.50wt％，
Mn：0.20～0.40wt％，
the balance being Mg and unavoidable impurities.
In the present invention, the Al content is preferably 5 to 7% by mass, more preferably 5.5 to 6.5% by mass, and most preferably 6% by mass; the Al element is a common strengthening element of the magnesium alloy, and can form Al-RE and Al-AE precipitated phase particles with RE and AE system elements, so that the material performance is effectively improved; when the aluminum element is less than 4%, the strength of the alloy is improved slightly, and the casting performance is poor; when the aluminum element is too high, a large amount of Mg is formed 17 Al 12 A brittle eutectic phase, which causes the reduction of strengthening effect and the reduction of alloy plasticity; the invention adopts aluminum element in the range of 4.5-7.5 wt%.
In the present invention, the La element is preferably contained in an amount of 2.0 to 2.5% by mass, more preferably 2.2 to 2.3% by mass; la element has the most obvious precipitation strengthening effect in light rare earth, the room high-temperature mechanical property of the alloy is improved by forming Al-La precipitation phase with high melting point, but the strengthening effect is not obvious when the La content is too low, and long rod-shaped precipitation phase with large size can be formed when the La content is too high, the mechanical property of the material is reduced due to the fact that matrix tissues are cut, and the La element ranges from 2.5 to 3.0wt% in order to obtain the best strengthening effect.
In the present invention, the mass content of the element Sm is preferably 0.6 to 0.9%, more preferably 0.7 to 0.8%; sm can prevent the further growth of large-size Al-La precipitated phases, so that the microstructure morphology of the alloy is optimized, and the strength and the plasticity of the material are improved; however, al 2 The Sm phase grows rapidly along with the increase of the content of Sm, absorbs more La elements, influences the composition proportion of the strengthening phase and weakens the strengthening effect, so that the addition amount of Sm and the La elements have a corresponding proportional relationship, and the range is 0.8-1.0%.
In the present invention, the RE (rare earth) other than La and Sm is preferably at least one selected from Y, gd; the content by mass of the RE except for La and Sm is preferably 0.03 to 0.09%, more preferably 0.04 to 0.08%, more preferably 0.05 to 0.07%, most preferably 0.06%; the heavy rare earth element is preferably dissolved in the matrix in the magnesium in a solid mode, so that the solid solubility of La/Sm is reduced, the precipitation efficiency of La/Sm is improved, and the multi-element microalloying strengthening effect is better, but more heavy rare earth can generate precipitation loss in a Mg-Al system to influence the quality and the cost of the alloy, and the addition amount of the heavy rare earth is 0.02-0.10%.
In the present invention, the mass content of Zn is preferably 0.7 to 0.9%, more preferably 0.8%; the Zn element has higher solid solubility in the magnesium alloy, can play a role in strengthening the magnesium alloy and is beneficial to improving the casting performance of the magnesium alloy; however, the higher Zn content is not favorable for the material to resist hot cracking, so that a small amount of Zn element is added into the alloy, and the content is 0.6-1.0%.
In the present invention, the content of Ca is preferably 0.20 to 0.45% by mass, more preferably 0.25 to 0.40% by mass, and most preferably 0.30 to 0.35% by mass; the Ca element can promote the refinement of magnesium alloy crystal grains in the solidification process, and a bottom viscosity oxide film is formed on the surface of the melt so as to improve the flame retardant property and the fluidity of the alloy; but the high calcium content can cause poor magnesium alloy casting hot cracking performance and obviously reduce the mechanical property of the material; the addition range of the calcium element is 0.15-0.50%.
In the present invention, the content of the Mn element is preferably 0.25 to 0.35% by mass, and more preferably 0.30% by mass; the Mn element can play a role in strengthening the magnesium alloy, promote the formation and dispersion distribution of an Al-RE phase and is beneficial to the improvement of the casting performance of the magnesium alloy; the amount of addition in the present invention is 0.20 to 0.40%.
In the present invention, the inevitable impurities are selected from Fe, si, cu, ni, etc., and the total impurity content is preferably not more than 0.2% by mass.
In the present invention, the mass ratio of La to Sm is preferably (2.8 to 3.2): 1, more preferably 3:1.
in the invention, the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy preferably comprises the following components:
Al：5.5～6.5wt％，
La：2.5～3.0wt％，
Sm：0.8～1.0wt％，
RE other than La/Sm: 0.02 to 0.05 weight percent,
Zn：0.8～0.9wt％，
Ca：0.15～0.25wt％，
Mn：0.25～0.30wt％。
the invention provides a preparation method of the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy in the technical scheme, which comprises the following steps:
melting an Mg ingot and an Al ingot, heating for the first time, then sequentially adding an Mg-La intermediate alloy, an Mg-Sm intermediate alloy and an Mg-Mn intermediate alloy, and carrying out first standing after melting to obtain a first melt;
keeping the temperature of the first melt at a second temperature, adding Mg-RE intermediate alloy and Mg-Ca intermediate alloy, melting, and then carrying out second standing to obtain a second melt;
heating the second melt to a third temperature, degassing, adding a flux, refining, cooling to a fourth temperature after the refining is finished, and standing for a third time;
and slagging off the alloy liquid after the third standing, and then casting and forming at a fifth temperature to obtain the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy.
In the present invention, the primary temperature rise is preferably performed under a protective atmosphere; the temperature of the primary heating is preferably 700-730 ℃, more preferably 715-725 ℃, and most preferably 720 ℃; the time for the first standing is preferably 25 to 35min, more preferably 28 to 32min, and most preferably 30min.
In the present invention, the mass content of La in the Mg — La master alloy is preferably 15 to 40%, more preferably 20 to 35%, and most preferably 25 to 30%; the mass content of Sm in the Mg-Sm master alloy is preferably 15 to 40 percent, more preferably 20 to 35 percent and most preferably 25 to 30 percent.
In the present invention, the melting is preferably followed by sufficiently stirring and then the first standing.
In the invention, the second temperature is preferably 700-730 ℃, more preferably 715-725 ℃, and most preferably 720 ℃; the time for the second standing is preferably 25 to 35min, more preferably 28 to 32min, and most preferably 30min.
In the present invention, the content of rare earth in the Mg-RE master alloy is preferably 15 to 40% by mass, more preferably 20 to 35% by mass, and most preferably 25 to 30% by mass.
In the present invention, the melting is preferably sufficiently stirred to be uniform for the second standing.
In the present invention, the third temperature is preferably 730 to 750 ℃, more preferably 735 to 745 ℃, and most preferably 740 ℃; the time of the refining treatment is preferably 20 to 35min, and more preferably 25 to 30min; the fourth temperature is preferably 690-700 ℃, and more preferably 695 ℃; the time for the third standing is preferably 20 to 30min, and more preferably 25min.
In the present invention, the fifth temperature is preferably 680 to 700 ℃, more preferably 685 to 695 ℃, and most preferably 690 ℃.
The method for casting molding is not particularly limited, and the casting molding technical scheme known to those skilled in the art can be adopted.
After the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy provided by the invention is cast, the alloy tensile strength, the yield strength and the elongation respectively reach: 240-260 MPa, 175-190 MPa and 4-7 percent, and has outstanding advantages in mechanical property compared with the traditional commercial AZ91/AM60 alloy.
Examples 1 to 7
The rare earth magnesium alloy is prepared by the following method:
under the protective atmosphere, melting Mg ingots and Al ingots, heating to 700-730 ℃, sequentially adding the Mg-La, mg-Sm and Mg-Mn alloys, fully and uniformly stirring after melting, and standing for 30 minutes;
keeping the temperature of the melt at 700-730 ℃, adding Mg-RE and Mg-Ca alloy, fully and uniformly stirring after melting, and standing for 30 minutes;
heating the melt to 730-750 ℃, degassing, adding a flux, refining for 20-35 min, cooling to 690-700 ℃ after refining, and standing for 20-30 min;
removing slag, and casting and molding at 680-700 ℃ to obtain the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy.
Comparative example 1
AZ91 magnesium alloy.
Comparative example 2
AM60 magnesium alloy.
Comparative examples 3 to 7
Rare earth magnesium alloys were prepared according to the methods of the examples.
Performance detection
The components of the rare earth magnesium alloys prepared in the examples and the comparative examples of the invention are detected according to the method of GBT 13748, and the detection results are shown in tables 1 and 2:
TABLE 1 compositions of rare earth magnesium alloys prepared in examples
TABLE 2 composition of rare earth magnesium alloy prepared by comparative example
FIG. 1 is the morphology of the as-cast microstructure of the magnesium alloy prepared in example 3, which is seen from the optical metallographic structure shown in FIG. 1A, and the alloy microstructure consists of an alpha-Mg matrix and island or block Al-RE eutectic structures with discontinuous network distribution of grain boundaries; as can be seen from the SEM structure morphology of FIG. 1B, the eutectic precipitated phase is mainly distributed at the grain boundary of the matrix, and in addition, the lamellar LPSO phase is seen in the grain boundary structure due to the high Zn and RE contents.
FIG. 2 is the element distribution analysis of the microstructure of the magnesium alloy prepared in example 3, which shows that the eutectic phase mainly precipitated in the alloy structure is Al-La phase, and the substitution phenomenon of Sm element for La is ubiquitous; by replacing La with Sm, the long rod-shaped Al-La phase is uniformly crushed, and the fracture action of the brittleness relative to a matrix is avoided, so that the improvement action of multicomponent rare earth alloying is brought, and the strength and the plasticity of the alloy are improved.
According to GB/T228.1 part 1 of the tensile test of metallic materials: room temperature test method ″ tests for tensile strength, yield strength, and elongation of the rare earth magnesium alloys prepared in the examples of the present invention and the comparative examples, and the test results are shown in tables 3 and 4:
TABLE 3 mechanical Properties of the rare earth magnesium alloys prepared in the examples
The test results in Table 3 show that the alloy of each embodiment has good strength and plasticity, the alloy prepared by the embodiment of the invention has the closest relationship between each performance and Al content and total rare earth content of the alloy, the performance is increased and then reduced along with the increase of the content of the rare earth, and the optimization effect of each performance is obviously weakened when the content of the rare earth is higher because the main strengthening phase Al of the alloy 11 RE 3 /Al 2 Increased number of RE phases and morphology changes. As can be seen from comparison among examples 1, 5 and 6, the low addition amount of Ca element has a good effect of improving the plasticity of the alloy, but as the content of Ca increases, the plasticity of the alloy is remarkably reduced, and the optimization effect on the strength begins to weaken. The Zn element has obvious influence on the yield strength and plasticity of the alloy, the yield strength is increased along with the increase of the Zn content, and the plasticity of the material is reduced along with the increase of the Zn content.
TABLE 4 mechanical properties of rare earth magnesium alloys prepared by comparative examples
As can be seen from the test results of table 4, the comparative commercial magnesium alloys (comparative example 1, comparative example 2) and the respective main alloying elements show significant changes in the material properties without any advantage in the properties compared to the optimized components of the examples, after departing from the scope of the present invention. After rare earth, alkaline earth and other alloying elements are added, the comprehensive performance of the alloy is superior to that of the commercial magnesium alloy which is widely adopted at present. As can be seen from the comparative examples 1 and 2, when the contents of Al and RE elements are too high, the material has coarsening and unevenness of microstructure due to rapid growth of precipitated phases, so that the material performance is rapidly reduced, and when the contents of the Al and RE elements are too low, the number density of alloy strengthening phases is remarkably reduced, so that the mechanical property of the alloy is insufficient and is lower than that of the conventional commercial magnesium alloy. As can be seen from comparative examples 3 and 4, excessive addition of Zn and Ca elements causes too high density of alloy precipitated phase and reduction of material plasticity under the action of Orwan mechanism, while addition of Zn and Ca elements weakens the precipitation strengthening action of the alloy, and causes insignificant improvement of alloy yield strength. As seen from comparative example 7, when the rare earth compounding ratio was changed, the strengthening effect of La element on strength was superior to that of Sm element, and the improvement effect on plasticity was inferior to that of Sm element.
After the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy provided by the invention is subjected to pressure casting, the tensile strength, the yield strength and the elongation of gold respectively reach: 240-260 MPa, 175-190 MPa and 4-7 percent, and has outstanding advantages in mechanical property compared with the traditional commercial AZ91/AM60 alloy.
While the invention has been described and illustrated with reference to specific embodiments thereof, such description and illustration are not intended to limit the invention. It will be clearly understood by those skilled in the art that various changes may be made to adapt a particular situation, material, composition of matter, substance, method or process to the objective, spirit and scope of this application without departing from the true spirit and scope of the invention as defined by the appended claims. All such modifications are intended to be within the scope of the claims appended hereto. Although the methods disclosed herein have been described with reference to particular operations performed in a particular order, it should be understood that these operations may be combined, sub-divided, or reordered to form equivalent methods without departing from the teachings of the present disclosure. Accordingly, unless specifically indicated herein, the order and grouping of the operations is not a limitation of the present application.
Claims (10)
1. An Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy comprises the following components:
Al：4.5～7.5wt％，
La：1.5～3.0wt％，
Sm：0.5～1.0wt％，
RE other than La and Sm: 0.02 to 0.10 weight percent,
Zn：0.6～1.0wt％，
Ca：0.15～0.50wt％，
Mn：0.20～0.40wt％，
the balance being Mg and unavoidable impurities.
2. The Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy according to claim 1, characterized by the composition:
Al：5.5～6.5wt％，
La：2.5～3.0wt％，
Sm：0.8～1.0wt％，
RE except La and Sm: 0.02 to 0.05 weight percent,
Zn：0.8～0.9wt％，
Ca：0.15～0.25wt％，
Mn：0.25～0.30wt％，
the balance being Mg and unavoidable impurities.
3. The Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy according to claim 1, wherein the mass ratio of La to Sm is (2.8 to 3.2): 1.
4. The Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy according to claim 1, wherein RE other than La and Sm is selected from at least one of Y, gd.
5. The method according to claim 1, characterized in that the mass content of the unavoidable impurities is < 0.2%.
6. A method for preparing the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy of claim 1, which comprises the following steps:
melting an Mg ingot and an Al ingot, heating for the first time, then sequentially adding an Mg-La intermediate alloy, an Mg-Sm intermediate alloy and an Mg-Mn intermediate alloy, and carrying out first standing after melting to obtain a first melt;
keeping the temperature of the first melt at a second temperature, adding Mg-RE intermediate alloy and Mg-Ca intermediate alloy, melting, and then carrying out second standing to obtain a second melt;
heating the second melt to a third temperature, degassing, adding a flux, refining, cooling to a fourth temperature after the refining is finished, and performing third standing;
and slagging off the alloy liquid after the third standing, and then casting and forming at a fifth temperature to obtain the Mg-Al-RE-Zn-Ca-Mn rare earth magnesium alloy.
7. The method according to claim 6, wherein the temperature of the primary heating is 700 to 730 ℃; the first standing time is 25-35 min.
8. The method of claim 6, wherein the second temperature is 700-730 ℃; and the second standing time is 25-35 min.
9. The method of claim 6, wherein the third temperature is 730 to 750 ℃; the fourth temperature is 690-700 ℃; and the third standing time is 20-30 min.
10. The method of claim 6, wherein the fifth temperature is 680-700 ℃.
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| CN116334462A (en) * | 2023-04-07 | 2023-06-27 | 中国科学院长春应用化学研究所 | Rare earth magnesium alloy and preparation method thereof |
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