Low-cost high-plasticity soluble magnesium alloy and preparation method thereof

Abstract

The invention belongs to the technical field of non-ferrous metal materials, and particularly relates to a low-cost high-plasticity soluble magnesium alloy and a preparation method thereof. The low-cost and high-plasticity soluble magnesium alloy comprises Zn, Mn, Ce, Cu, Al and the balance Mg and inevitable impurities, the low-cost and high-plasticity soluble magnesium alloy is prepared through raw material smelting, casting, homogenization treatment, hot extrusion and heat treatment, the tensile strength of the low-cost and high-plasticity soluble magnesium alloy can reach 270 MPa, the yield strength of the low-cost and high-plasticity soluble magnesium alloy can reach 210 MPa, the ductility of the low-cost and high-plasticity soluble magnesium alloy can reach 32%, meanwhile, the dissolution rate of the low-cost and high-plasticity soluble magnesium alloy can reach 90 mg / (cm < 2 >. H), and the low-cost and high-plasticity soluble magnesium alloy can be widely applied to the field of magnesium alloy production. The system can be widely applied to the fields of national defense, energy mining and medical treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-ferrous metal materials, and more specifically relates to a low-cost, high-plasticity soluble magnesium alloy and a preparation method thereof. Background Art

[0002] In shale oil and gas exploitation, the packer devices such as bridge plugs and fracturing balls used in traditional hydraulic fracturing technology are mostly made of insoluble materials or incompletely soluble materials. After use, they need to be drilled or removed by a second downhole operation, which is likely to cause blockage, increase the exploitation cost and seriously affect the safety of exploitation. Therefore, developing soluble downhole materials for shale oil and gas exploitation has become the key to solving the problem.

[0003] Magnesium alloy is one of the lightest structural metals known to be applicable in the industrial field at present. The density of pure magnesium is 1.74 g·cm -3 , and magnesium and its alloys have the advantages of high specific stiffness, good thermal and electrical conductivity, damping and vibration reduction, electromagnetic shielding, easy processing and forming, and easy recycling, making them ideal materials for downhole tools. However, the magnesium alloys used in existing downhole tools have low plasticity and are difficult to meet the requirements of downhole soluble tools. Therefore, improving the room temperature plasticity of soluble magnesium alloys is a key technology affecting their application in the energy exploitation field. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-cost, high-plasticity soluble magnesium alloy and a preparation method thereof to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: Provide a low-cost, high-plasticity soluble magnesium alloy. By mass percentage, except for Mg, the components include: 1.3-2.7% of Zn, 0.5-2% of Mn, 0.5-1.5% of Ce, 0.05-0.4% of Cu, 0.01-0.05% of Al, and inevitable impurities.

[0007] Further, by mass percentage, the components of the low-cost, high-plasticity soluble magnesium alloy are: 1.3-2.7% of Zn, 0.5-2% of Mn, 0.5-1.5% of Ce, 0.05-0.4% of Cu, 0.01-0.05% of Al, and the balance is Mg and inevitable impurities.

[0008] The total amount of inevitable impurities in the present invention is not higher than 0.2%.

[0009] In the present invention, the mass percentage of Zn is 1.3 - 2.7%, which can further improve the strength of the magnesium alloy, and at the same time can also increase the fluidity of the alloy and improve the casting performance; the mass percentage of Mn is 0.5 - 2%, which can improve the corrosion resistance of the magnesium alloy, and at the same time, by refining the grains, improve the strength and toughness of the alloy; the mass percentage of Ce is 0.5 - 1.5%, which can refine the grains, improve the strength, plasticity and toughness of the alloy. In addition, Ce can also improve the high-temperature performance of the magnesium alloy and enhance the creep resistance of the alloy at high temperatures; the mass percentage of Cu is 0.05 - 0.4%, and Cu can greatly improve the solubility of the magnesium alloy; the mass percentage of Al is 0.01 - 0.05%, which can improve the strength and hardness of the magnesium alloy through solid solution strengthening and aging strengthening.

[0010] The second technical solution of the present invention: Provide a preparation method of a low-cost and high-plasticity soluble magnesium alloy, and the steps include:

[0011] Prepare raw materials according to the component ratio of the above-mentioned low-cost and high-plasticity soluble magnesium alloy;

[0012] After melting the raw materials, through casting, homogenization treatment, hot extrusion and heat treatment, the low-cost and high-plasticity soluble magnesium alloy is prepared.

[0013] Further, the raw materials include various ones among magnesium ingots, zinc ingots, anhydrous manganese chloride, magnesium-cerium master alloy, magnesium-copper master alloy, pure copper and aluminum ingots to support the component composition of the above-mentioned low-cost and high-plasticity soluble magnesium alloy.

[0014] Further, the raw materials also include preheating treatment before melting, wherein the temperature of the preheating treatment is 200°C and the time is 2 - 3h.

[0015] Further, the steps of the melting include: melting RJ-5 solvent and magnesium ingot at 680°C, and the melting time is 3 - 4h; then raising the temperature to 725 - 735°C, adding zinc ingot and anhydrous manganese chloride, and continuing to raise the temperature to 745 - 755°C, then adding magnesium-cerium master alloy and aluminum ingot, as well as magnesium-copper master alloy or pure copper, fully stirring and then holding for 15min, wherein anhydrous manganese chloride and RJ-5 solvent are mixed in a mass ratio of 1:1 and then added; then using RJ-5 solvent for refining, the refining temperature is 735 - 745°C, and the refining time is 15 - 30min to complete the melting.

[0016] Optionally, when melting the magnesium ingot, the mass ratio of the RJ-5 solvent to the magnesium ingot is 1:32.

[0017] Optionally, the addition amount of the RJ-5 solvent during refining is 2% of the mass of the magnesium ingot.

[0018] The smelting step of the present invention is carried out under a protective atmosphere, wherein the protective atmosphere is provided by a mixed gas of SF6 and CO2.

[0019] Further, the homogenization treatment is carried out at 290 - 310 °C for 5 - 7 h, and then water-cooled at 40 - 50 °C.

[0020] Homogenization treatment of the cast rod can effectively improve the tissue uniformity, refine the grains, eliminate the residual stress, improve the plasticity, and provide a strong guarantee for realizing high-quality and high-performance magnesium alloy hot extrusion products.

[0021] Further, in the hot extrusion, the temperature of the ingot is 295 - 325 °C, the temperature of the die is 420 - 440 °C, the extrusion ratio is 13:1, the extrusion pressure is 15 - 20 MPa, and the extrusion speed is 0.3 - 0.5 mm / s.

[0022] Hot extrusion can refine the structure and grains of the magnesium alloy material, eliminate defects such as pores and shrinkage porosity in the as-cast structure, and effectively improve its mechanical properties.

[0023] Further, the heat treatment is carried out at 320 - 360 °C for 2 - 6 h, and then water-cooled at 40 - 50 °C.

[0024] Heat treatment can effectively improve the strength and hardness of the magnesium alloy material, improve the plasticity and toughness, and is a key technical link to realize its high performance and meet different application requirements.

[0025] In the composition design of magnesium alloys, the selection of elements and processes such as homogenization treatment, hot extrusion, and heat treatment do not exist in isolation. By reasonably regulating these factors, the comprehensive performance of magnesium alloys can be optimized to meet the diverse needs of different application fields.

[0026] The third technical solution of the present invention: Provide an application of the above low-cost and high-plasticity soluble magnesium alloy in energy extraction.

[0027] The present invention discloses the following technical effects:

[0028] The low-cost and high-plasticity soluble magnesium alloy prepared by the present invention has excellent strength and plasticity. Its tensile strength can reach 270 MPa, the yield strength can reach 210 MPa, the elongation can reach 32%, and the dissolution rate (93 °C, 3% KCl) can reach 90 mg / (cm 2 ·h). Moreover, the preparation cost is low, the method is simple, the process stability is good, and industrial production can be realized, and it has broad application prospects in the fields of national defense, energy extraction, medical treatment, etc. Description of the Drawings

[0029] The accompanying drawings, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0030] Figure 1 It is a schematic process flow diagram of a specific implementation of the present invention. Specific embodiments

[0031] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation to the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] It should be understood that the terms described in the present invention are only used to describe specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0033] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0034] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and embodiments are only exemplary.

[0035] It should be noted that the aspects not detailedly described in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0036] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0037] As used in the specific embodiments of the present invention, "room temperature" and "normal temperature" both refer to 20 - 30 °C.

[0038] The raw materials and reagents used in the specific implementation of the present invention are all commercially available products.

[0039] In the specific implementation of the present invention, the purity of the magnesium ingot is 99.99%; the purity of the zinc ingot is 99.99%; the mass fraction of manganese in anhydrous manganese chloride is 43%; the mass fraction of cerium in the magnesium-cerium master alloy is 30%; the purity of pure copper is 99%; the purity of the aluminum ingot is 99.99%.

[0040] In the specific implementation of the present invention, the alloying efficiency of the zinc ingot is about 100%, the alloying efficiency of anhydrous manganese chloride is about 75%, the alloying efficiency of the magnesium-cerium master alloy is about 100%, the alloying efficiency of pure copper is about 95%, and the alloying efficiency of pure aluminum is about 100%.

[0041] Example 1

[0042] Preparation method of low-cost and high-plasticity soluble magnesium alloy:

[0043] S1. According to the prepared low-cost and high-plasticity soluble magnesium alloy, prepare the required raw materials: magnesium ingot, zinc ingot, anhydrous manganese chloride, magnesium-cerium master alloy, pure copper, and aluminum ingot according to the mass percentages of Zn 2.43%, Mn 1.76%, Ce 1.42%, Cu 0.34%, Al 0.03% and the balance of Mg, and preheat at 200 °C for 2 - 3 hours;

[0044] S2. Set the temperature of the electric furnace to 680 °C, preheat the crucible until the surface turns dark red, sprinkle RJ-5 solvent at the bottom and the wall of the crucible, then put in the magnesium ingot, sprinkle part of the RJ-5 solvent for each layer of magnesium ingot put in, the melting time of the magnesium ingot is 3 hours, and the mass ratio of the RJ-5 solvent to the magnesium ingot during the melting of the magnesium ingot is 1:32; after the magnesium ingot melts, raise the temperature of the melt to 730 ± 5 °C, add the zinc ingot and anhydrous manganese chloride, and add the anhydrous manganese chloride after mixing it with the RJ-5 solvent according to a mass ratio of 1:1; then add the magnesium-cerium master alloy, pure copper, and aluminum ingot, stir well and keep warm for 15 min; then carry out refining, the refining uses RJ-5 solvent (2% of the mass of the magnesium ingot), the refining temperature is 740 ± 5 °C, the refining time is 15 min, and finally carry out ingot casting to obtain a magnesium alloy ingot, scrape the slag on the surface of the melt clean before casting, and the casting temperature is between 670 °C and 720 °C; the melting process in this step is carried out under a protective atmosphere, and the protective atmosphere is a mixed gas of SF6 and CO2;

[0045] S3. Put the magnesium alloy ingot obtained in step S2 into an electric resistance furnace, heat it to 300 ± 2 °C, keep warm for 6 h, and after homogenization, cool it with water between 40 - 50 °C to obtain a homogenized magnesium alloy ingot;

[0046] S4. Place the homogeneous magnesium alloy ingot obtained in step S3 into a resistance furnace and heat it to 300 °C, and preheat the mold to 430 °C, then perform hot extrusion with an extrusion ratio of 13:1, an extrusion pressure of 19 MPa, and an extrusion speed of 0.5 mm / s to obtain a hot-extruded magnesium alloy sheet;

[0047] S5. Place the hot-extruded magnesium alloy sheet obtained in step S4 into a heat treatment furnace for heat treatment at a heat treatment temperature of 320 °C for 4 hours, and then perform water cooling between 40 - 50 °C after the heat treatment is completed to obtain a low-cost, high-plasticity soluble magnesium alloy.

[0048] Example 2

[0049] Preparation method of low-cost, high-plasticity soluble magnesium alloy:

[0050] S1. According to the prepared low-cost, high-plasticity soluble magnesium alloy, prepare the required raw materials by mass percentage: 1.88% Zn, 1.0% Mn, 0.86% Ce, 0.19% Cu, 0.04% Al, and the balance Mg, namely magnesium ingots, zinc ingots, anhydrous manganese chloride, magnesium-cerium master alloy, pure copper, and aluminum ingots, and preheat them at 200 °C for 2 - 3 hours; S2. Set the temperature of the electric melting furnace to 680 °C, preheat the crucible until its surface turns dark red, sprinkle RJ-5 solvent at the bottom and the wall of the crucible, then put in magnesium ingots, and sprinkle part of the RJ-5 solvent every time a layer of magnesium ingots is put in. The melting time of the magnesium ingots is 3 hours, and the mass ratio of the RJ-5 solvent to the magnesium ingots during the melting process of the magnesium ingots is 1:32; after the magnesium ingots are melted, raise the temperature of the melt to 730 ± 5 °C, add zinc ingots and anhydrous manganese chloride, where the anhydrous manganese chloride is mixed with the RJ-5 solvent in a mass ratio of 1:1 and then added; then add the magnesium-cerium master alloy, pure copper, and aluminum ingots, stir well and keep warm for 15 min; then perform refining. The refining uses RJ-5 solvent (2% of the mass of the magnesium ingots), the refining temperature is 740 ± 5 °C, and the refining time is 15 min. Finally, perform ingot casting to obtain a magnesium alloy ingot. Before casting, scrape the slag on the surface of the melt clean, and the casting temperature is between 670 °C and 720 °C; the melting process in this step is carried out under a protective atmosphere, and the protective atmosphere is a mixed gas of SF6 and CO2;

[0051] S3. Place the magnesium alloy ingot obtained in step S2 into a resistance furnace and heat it to 300 ± 2 °C, keep warm for 6 h, and perform water cooling between 40 - 50 °C after homogenization is completed to obtain a homogeneous magnesium alloy ingot;

[0052] S4. Place the homogeneous magnesium alloy ingot obtained in step S3 into a resistance furnace and heat it to 300 °C, and preheat the mold to 430 °C, then perform hot extrusion with an extrusion ratio of 13:1, an extrusion pressure of 17 MPa, and an extrusion speed of 0.4 mm / s to obtain a hot-extruded magnesium alloy sheet;

[0053] S5. Place the hot-extruded magnesium alloy sheet obtained in step S4 in a heat treatment furnace for heat treatment. The heat treatment temperature is 320 °C, and the heat treatment time is 4 hours. After the heat treatment is completed, water-cool it between 40 - 50 °C to obtain a low-cost and high-plasticity soluble magnesium alloy.

[0054] Example 3

[0055] Preparation method of low-cost and high-plasticity soluble magnesium alloy:

[0056] S1. According to the prepared low-cost and high-plasticity soluble magnesium alloy, prepare the required raw materials by mass percentage: 1.6% Zn, 0.56% Mn, 0.74% Ce, 0.1% Cu, 0.05% Al, and the balance Mg: magnesium ingots, zinc ingots, anhydrous manganese chloride, magnesium-cerium master alloy, pure copper, aluminum ingots, and preheat them at 200 °C for 2 - 3 hours; S2. Set the temperature of the electric melting furnace to 680 °C, preheat the crucible until the surface turns dark red, sprinkle RJ-5 solvent at the bottom and the wall of the crucible, then put in the magnesium ingots, and sprinkle part of the RJ-5 solvent for each layer of magnesium ingots put in. The melting time of the magnesium ingots is 3 hours, and the mass ratio of the RJ-5 solvent to the magnesium ingots during the melting of the magnesium ingots is 1:32; after the magnesium ingots are melted, raise the temperature of the melt to 730 ± 5 °C, add zinc ingots and anhydrous manganese chloride, and add the anhydrous manganese chloride after mixing it with the RJ-5 solvent according to a mass ratio of 1:1; then add the magnesium-cerium master alloy, pure copper and aluminum ingots, stir well and keep warm for 15 min; then carry out refining. The refining uses RJ-5 solvent (2% of the mass of the magnesium ingots), the refining temperature is 740 ± 5 °C, the refining time is 15 min, and finally carry out ingot casting to obtain a magnesium alloy ingot. Before casting, scrape off the slag on the surface of the melt, and the casting temperature is between 670 °C and 720 °C; the melting process of this step is carried out under a protective atmosphere, and the protective atmosphere is a mixed gas of SF6 and CO2;

[0057] S3. Put the magnesium alloy ingot obtained in step S2 into a resistance furnace and heat it to 300 ± 2 °C, keep warm for 6 h, and after homogenization is completed, water-cool it between 40 - 50 °C to obtain a homogenized magnesium alloy ingot;

[0058] S4. Put the homogenized magnesium alloy ingot obtained in step S3 into a resistance furnace and heat it to 300 °C, and preheat the mold to 430 °C, then carry out hot extrusion. The extrusion ratio is 13:1, the extrusion pressure is 15 MPa, and the extrusion speed is 0.3 mm / s to obtain a hot-extruded magnesium alloy sheet;

[0059] S5. Place the hot-extruded magnesium alloy sheet obtained in step S4 in a heat treatment furnace for heat treatment. The heat treatment temperature is 320 °C, and the heat treatment time is 4 hours. After the heat treatment is completed, water-cool it between 40 - 50 °C to obtain a low-cost and high-plasticity soluble magnesium alloy.

[0060] Comparative Example 1

[0061] Compared with Example 2, the difference lies in that the magnesium alloy ingot prepared in step S2 is not subjected to homogenization treatment, hot extrusion and heat treatment processes, that is, the magnesium alloy ingot prepared in step S2 is used as the final product.

[0062] Comparative Example 2

[0063] Compared with Example 2, the difference lies in that the magnesium alloy ingot prepared in step S4 is not subjected to heat treatment process, that is, the magnesium alloy sheet prepared in step S4 is used as the final product.

[0064] Test Example

[0065] Components were prepared by the methods of the above Examples 1-3 and Comparative Examples 1-2, and mechanical property tests and dissolution property tests were carried out. The results are shown in Table 1.

[0066] Table 1 Mechanical properties and dissolution properties of low-cost high-plasticity soluble magnesium alloy sheets

[0067]

[0068] As can be seen from Table 1, for a low-cost high-plasticity soluble magnesium alloy prepared in an embodiment of the present invention, the tensile strength can reach 270 MPa, the yield strength can reach 210 MPa, the elongation rate can reach 32%, and the dissolution rate can reach (93 °C, 3% KCl) 60-90 mg / (cm 2 ·h).

[0069] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0070] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-cost, highly plastic and soluble magnesium alloy, characterized in that, By mass percentage, except for Mg, the components include: Zn 1.3 - 2.7%, Mn 0.5 - 2%, Ce 0.5 - 1.5%, Cu 0.05 - 0.4% and Al 0.01 - 0.05%, as well as inevitable impurities.

2. The low-cost and high-plasticity soluble magnesium alloy according to claim 1, wherein By mass percentage, the components are: Zn 1.3 - 2.7%, Mn 0.5 - 2%, Ce 0.5 - 1.5%, Cu 0.05 - 0.4% and Al 0.01 - 0.05%, and the balance is Mg and inevitable impurities.

3. A preparation method of a low-cost and high-plasticity soluble magnesium alloy, characterized in that the steps Including: Prepare raw materials according to the component ratio of the low-cost high-plasticity soluble magnesium alloy described in Claim 1 or 2; After melting the raw materials, through casting, homogenization treatment, hot extrusion and heat treatment, the low-cost high-plasticity soluble magnesium alloy is prepared.

4. The preparation method according to claim 3, characterized in that, The raw materials include various ones among magnesium ingots, zinc ingots, anhydrous manganese chloride, Mg-Ce master alloy, Mg-Cu master alloy, pure copper and aluminum ingots; and / or, the raw materials also include preheating treatment before melting, wherein the temperature of the preheating treatment is 200°C and the time is 2 - 3 h.

5. The preparation method according to claim 4, characterized in that, The steps of the melting include: melting RJ-5 solvent and magnesium ingots at 680°C for 3 - 4 h; then raising the temperature to 725 - 735°C, adding zinc ingots and anhydrous manganese chloride, continuing to raise the temperature to 745 - 755°C, then adding Mg-Ce master alloy and aluminum ingots, as well as Mg-Cu master alloy or pure copper, fully stirring and then holding for 15 min, wherein the anhydrous manganese chloride is added after being mixed with the RJ-5 solvent according to the mass ratio of 1:1; then refining with the RJ-5 solvent, the refining temperature is 735 - 745°C and the refining time is 15 - 30 min, completing the melting.

6. The preparation method according to claim 5, characterized in that, When melting the magnesium ingots, the mass ratio of the RJ-5 solvent to the magnesium ingots is 1:32; and / or, the addition amount of the RJ-5 solvent during refining is 2% of the mass of the magnesium ingots.

7. The preparation method according to claim 3, characterized in that The homogenization treatment is to homogenize at 290 - 310°C for 5 - 7 h, and then water-cool at 40 - 50°C.

8. The preparation method according to claim 3, characterized in that, In the hot extrusion, the temperature of the ingot is 295 - 325°C, the temperature of the die is 420 - 440°C, the extrusion ratio is 13:1, the extrusion pressure is 15 - 20 MPa, and the extrusion speed is 0.3 - 0.5 mm / s.

9. The preparation method according to claim 3, characterized in that The heat treatment is to perform heat treatment at 320 - 360°C for 2 - 6 h, and then water-cool at 40 - 50°C.

10. Application of the low-cost high-plasticity soluble magnesium alloy described in Claim 1 or 2 in energy exploitation.

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