High-toughness and easily soluble magnesium alloy and its preparation method

Abstract

The present invention discloses a high-toughness and easily soluble magnesium alloy and a preparation method thereof. The high-toughness and easily soluble magnesium alloy contains the following components by mass percentage: 1% to 6% of Zn element, 1% to 4% of Ni element, 0.2% to 4% of element A, 0.2% to 1% of element B, and the balance is Mg element; the element A is at least one of Gd element and Y element, and the element B is at least one of Ga element and In element; the high-toughness and easily soluble magnesium alloy contains 3 kinds of intragranular precipitation phases with regular shapes, and the intragranular precipitation phases are basal plane-oriented MgZn phase, prism plane-oriented MgZn phase, and non-oriented MgNi phase. The high-toughness and easily soluble magnesium alloy of the present invention simultaneously has high strength, high elongation rate, and high dissolution rate. The tensile strength at room temperature is ≥240 MPa, the yield strength is ≥160 MPa, the elongation rate is ≥8%, and the dissolution rate in water at room temperature is ≥30 mg·cm<supgt;‑2< / supgt;·h<supgt;‑1< / supgt>.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal materials and processing, and specifically relates to a high-toughness and easily soluble magnesium alloy and a preparation method thereof. Background Art

[0002] Due to its easy-to-corrode properties, magnesium alloys have been gradually used in industrial fields such as drilling in recent years. In order to accelerate the reaction rate of magnesium alloys with liquids such as water, adding Ni, Ga, and In elements has become a common means. However, these elements can cause brittle fracture of magnesium alloys, not only insufficient elongation, but also a significant decrease in strength. To this end, researchers continue to add rare earth elements such as Gd and Y, in order to improve the strength and elongation of magnesium alloys, thereby achieving a toughening effect. Unfortunately, when the rare earth element content is low, the improvement effect on the strength and elongation of magnesium alloys is not obvious enough. When the rare earth element content is high, although the toughness of magnesium alloys can be improved, the dissolution rate will decrease. At present, precipitation strengthening is a common means to improve the strength of magnesium alloys, such as adding a large amount of rare earth elements to produce a cylindrically oriented intracrystalline precipitation phase, or adding a large amount of Al elements to produce a basal plane oriented intracrystalline precipitation phase, etc. However, the disadvantage of the above precipitation strengthening is that the precipitation phase is single in type, which can only improve the strength, but has no contribution to the elongation, and may even damage the elongation. In addition, in order to accelerate the reaction between magnesium alloy and water, adding elements such as Ni, Ga, and In to form a micro-galvanic couple composed of anode Mg and cathode compounds inside the magnesium alloy is currently a common method for preparing soluble magnesium alloys. However, the above elements usually induce brittle fracture of magnesium alloys, and it is impossible to prepare magnesium alloys with high strength, high elongation and high dissolution rate. Therefore, how to prepare magnesium alloys with high strength, high elongation and high dissolution rate has always been a problem that plagues researchers. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a high-toughness, easily soluble magnesium alloy having high strength, high elongation and high dissolution rate and a preparation method thereof.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0005] A high-toughness and easily soluble magnesium alloy comprises the following components, measured by mass percentage: 1% to 6% of Zn element, 1% to 4% of Ni element, 0.2% to 4% of A element, 0.2% to 1% of B element, and the balance is Mg element; the A element is at least one of Gd element and Y element, and the B element is at least one of Ga element and In element; the high-toughness and easily soluble magnesium alloy comprises three kinds of intracrystalline precipitation phases with regular shapes, and the intracrystalline precipitation phases are basal plane oriented MgZn phase, columnar plane oriented MgZn phase, and non-oriented MgNi phase.

[0006] For the above-mentioned high-toughness and easily soluble magnesium alloy, further improved, the high-toughness and easily soluble magnesium alloy contains grain boundary compounds with irregular shapes. When the B element is the Ga element, the grain boundary compounds are MgNi compounds and MgGa compounds; when the B element is the In element, the grain boundary compounds are MgNi compounds and MgIn compounds; when the B element is the Ga element and the In element, the grain boundary compounds are MgNi compounds, MgGa compounds and MgIn compounds.

[0007] For the above-mentioned high-toughness and easily soluble magnesium alloy, further improved, when the A element is the Gd element, neither the intragranular precipitation phase nor the grain boundary compounds contain the Gd element; when the A element is the Y element, neither the intragranular precipitation phase nor the grain boundary compounds contain the Y element; when the A element is the Gd element and the Y element, neither the intragranular precipitation phase nor the grain boundary compounds contain the Gd element and the Y element.

[0008] For the above-mentioned high-toughness and easily soluble magnesium alloy, further improved, when the content of the Zn element is 1% - 4%, the content of the A element is 2% - 4%, and the content of the B element is 0.6% - 1%; when the content of the Zn element is 4% - 6%, the content of the A element is 0.2% - 2%, and the content of the B element is 0.2% - 0.6%.

[0009] For the above-mentioned high-toughness and easily soluble magnesium alloy, further improved, when the B element is the Ga element and the In element, the content of the Ga element ≤ the content of the In element.

[0010] For the above-mentioned high-toughness and easily soluble magnesium alloy, further improved, the Schmid factor of the basal plane slip of the high-toughness and easily soluble magnesium alloy is 0.25 - 0.45.

[0011] For the above-mentioned high-toughness and easily soluble magnesium alloy, further improved, the Schmid factor of the basal plane slip of the high-toughness and easily soluble magnesium alloy is 0.3 - 0.4.

[0012] As a general technical concept, the present invention also provides a preparation method of a high-toughness and easily soluble magnesium alloy, including the following steps:

[0013] S1. According to the mass percentages of the components in the magnesium alloy, weigh the required raw materials, mix them evenly, melt, refine, and cast to obtain an ingot; the magnesium alloy, by mass percentage, contains the following components: 1% - 6% of Zn element, 1% - 4% of Ni element, 0.2% - 4% of A element, 0.2% - 1% of B element, and the balance is Mg element; the A element is at least one of Gd element and Y element, and the B element is at least one of Ga element and In element;

[0014] S2. Homogenize the ingot; the temperature of the homogenization treatment is 360°C to 450°C, and the time of the homogenization treatment is 6 hours to 48 hours;

[0015] S3. Perform hot deformation on the material after homogenization treatment; the temperature of the hot deformation is 330°C to 420°C, and the total deformation amount of the hot deformation is 70% to 90%;

[0016] S4. Perform aging treatment on the material after hot deformation; the temperature of the aging treatment is 170°C to 220°C, and the time of the aging treatment is 6 hours to 96 hours.

[0017] For the above preparation method of the high-toughness and easily soluble magnesium alloy, further improved, when the content of Zn element is 1% to 4%, the temperature of the hot deformation is 370°C to 420°C, and the temperature of the aging treatment is 200°C to 220°C;

[0018] When the content of Zn element is 4% to 6%, the temperature of the hot deformation is 330°C to 370°C, and the temperature of the aging treatment is 170°C to 200°C.

[0019] For the above preparation method of the high-toughness and easily soluble magnesium alloy, further improved, in step S3, the hot deformation is at least one of extrusion, forging, and rolling; the deformation amount of a single pass of the extrusion is 70% to 90%, the deformation amount of a single pass of the forging is 30% to 50%, and the deformation amount of a single pass of the rolling is 10% to 40%.

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] (1) Aiming at the defects that existing magnesium alloys cannot simultaneously possess high strength, high elongation rate, and high dissolution rate, the present invention creatively proposes a high-toughness and easily soluble magnesium alloy. First, 1% - 6% of Zn element is added. By utilizing the characteristics that Zn element is easy to precipitate and the precipitated phases have various orientations, a microstructure containing both basal-plane-oriented MgZn precipitated phases and columnar-plane-oriented MgZn precipitated phases is prepared, enabling the interaction between dislocations and precipitated phases to occur on different crystal planes, avoiding the damage of stress concentration to the elongation rate, and thus simultaneously possessing high strength and high elongation rate. Secondly, 1% - 4% of Ni element is added. By means of hot deformation and aging treatment, a large number of intragranular MgNi precipitated phases are induced in the Mg matrix. By utilizing the characteristic that the MgNi phase has no obvious orientation, stress concentration generated after its interaction with dislocations is avoided, so that while obtaining a high dissolution rate, the elongation rate and strength are not damaged. Then, 0.2% - 4% of element A (element A is at least one of Gd element and Y element) is added, such that element A does not participate in the formation of intragranular precipitated phases and grain boundary compounds. In this way, not only can element A stably provide solid solution strengthening, but also the magnesium alloy can have a suitable Schmid factor for basal plane slip, and the damage of compounds containing element A to the elongation rate and dissolution rate of the magnesium alloy is avoided. Finally, 0.2% - 1% of element B (element B is at least one of Ga element and In element) is added, which can not only enable the magnesium alloy to react rapidly with water at room temperature, but also avoid damaging the strength and elongation rate, thereby obtaining a magnesium alloy that simultaneously possesses high strength, high elongation rate, and high dissolution rate. The high-toughness and easily soluble magnesium alloy of the present invention has a tensile strength ≥ 240 MPa, a yield strength ≥ 160 MPa, an elongation rate ≥ 8% at room temperature, and a dissolution rate ≥ 30 mg·cm -2 ·h -1 . In addition, the added Zn element has a low price, and the total content of the added rare earth element A does not exceed 4%, greatly reducing the raw material cost of the high-strength and soluble magnesium alloy.

[0022] (2) For the high-toughness and easily soluble magnesium alloy of the present invention, by optimizing the ratios of Zn element, element A, and element B, that is, when the content of Zn element is 1% - 4%, the content of element A is 2% - 4%, and the content of element B is 0.6% - 1%; when the content of Zn element is 4% - 6%, the content of element A is 0.2% - 2%, and the content of element B is 0.2% - 0.6%, it can not only avoid the formation of MgGdZn and MgYZn compounds that damage the elongation rate, but also avoid reducing the dissolution rate.

[0023] (3) For the high-toughness and easily soluble magnesium alloy of the present invention, when element B is Ga element and In element, the ratios of Ga element and In element are further optimized, that is, the content of Ga element ≤ the content of In element. A high content of In can not only avoid inducing brittle fracture but also improve the dissolution rate.

[0024] (4) The present invention also provides a method for preparing a high-toughness and easily soluble magnesium alloy. The ingot melted according to the magnesium alloy composition is sequentially subjected to homogenization treatment, hot deformation, and aging treatment. During the hot deformation process, dynamic precipitation occurs, and then aging treatment is carried out on this basis, so as to obtain intragranular precipitation phases and grain boundary compounds with multiple sizes, multiple orientations, and multiple components, that is, a large number of basal-plane-oriented MgZn phases, prismatic-plane-oriented MgZn phases, and non-oriented MgNi phases are induced in the Mg matrix by hot deformation and aging treatment. The preparation method of the present invention has the advantages of simple process, low requirements for equipment tonnage and energy consumption, convenient operation, and high efficiency.

[0025] (5) In the preparation method of the present invention, when the content of Zn element is 1% - 4%, the temperature of hot deformation is further optimized to be 370°C - 420°C, and the temperature of aging treatment is 200°C - 220°C, which can further improve the strength, elongation, and dissolution rate of the magnesium alloy. This is because when the Zn content is low, the basal texture of the magnesium alloy is strong, and it is easier to process and form at high temperature, and it is easier to obtain various intragranular precipitation phases and grain boundary compounds during high-temperature aging.

[0026] (6) In the preparation method of the present invention, when the content of Zn element is 4% - 6%, the temperature of hot deformation is further optimized to be 330°C - 370°C, and the temperature of aging treatment is 170°C - 200°C, which can further improve the strength, elongation, and dissolution rate of the magnesium alloy. This is because when the Zn content is high, the basal texture of the magnesium alloy is weak, and low-temperature deformation can not only save energy but also avoid the high-temperature brittleness induced by Zn element, and low-temperature aging can also avoid the coarsening of intragranular precipitation phases and grain boundary compounds. Description of the Drawings

[0027] Figure 1 It is the TEM microstructure diagram of the high-toughness and easily soluble magnesium alloy prepared in Example 1 of the present invention.

[0028] Figure 2 It is the metallographic microstructure diagram of the high-toughness and easily soluble magnesium alloy prepared in Example 1 of the present invention.

[0029] Figure 3 It is the columnar diagram of the Schmid factor of basal slip of the high-toughness and easily soluble magnesium alloy prepared in Example 1 of the present invention.

[0030] Figure 4 It is the TEM microstructure diagram of the magnesium alloy prepared in Comparative Example 1 of the present invention.

[0031] Figure 5 It is the metallographic microstructure diagram of the magnesium alloy prepared in Comparative Example 1 of the present invention.

[0032] Figure 6 It is the columnar diagram of the Schmid factor of basal slip of the magnesium alloy prepared in Comparative Example 1 of the present invention. Detailed implementation mode

[0033] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0034] Example 1:

[0035] A high-toughness and easily soluble magnesium alloy of the present invention, by mass percentage, contains the following components: 1.5% Zn element, 3.5% Ni element, 2% Gd element, 1% Y element, 0.12% Ga element, 0.5% In element, and the balance is Mg element.

[0036] A preparation method of the high-toughness and easily soluble magnesium alloy of this example includes the following steps:

[0037] S1. According to the mass percentage of each component in the magnesium alloy, weigh the required raw materials, mix them evenly, melt, refine, and cast to obtain an ingot.

[0038] S2. Perform homogenization treatment on the ingot, that is, keep it at 450 °C for 6 hours.

[0039] S3. Perform hot deformation on the homogenized ingot, that is, first perform one-pass forging deformation, the forging temperature is 410 °C, and the single-pass deformation amount is 30%; then perform one-pass rolling deformation, the rolling temperature is 400 °C, and the single-pass deformation amount is 30%; the total deformation amount of forging and rolling is 76%.

[0040] S4. Perform aging treatment on the rolled material, that is, keep it at 220 °C for 90 hours to obtain a high-toughness and easily soluble magnesium alloy, abbreviated as Mg-1.5Zn-3.5Ni-2Gd-1Y-0.12Ga-0.5In alloy, marked as Sample No. 1.

[0041] The high-toughness and easily soluble magnesium alloy prepared in this example, as Figure 1 and Figure 2 shown, contains 3 kinds of regularly shaped intragranular precipitation phases inside, namely basal plane-oriented MgZn phase, prism plane-oriented MgZn phase, and non-oriented MgNi phase; irregularly shaped grain boundary compounds are also contained inside the sample, namely MgNi compound, MgGa compound, and MgIn compound. In addition, as Figure 3 shown, the Schmid factor of basal plane slip of this sample is 0.32.

[0042] Comparative Example 1:

[0043] A magnesium alloy, by mass percentage, contains the following components: 0.5% Zn element, 3.5% Ni element, 2% Gd element, 1% Y element, 0.12% Ga element, 0.5% In element, and the balance is Mg element.

[0044] The preparation method of this magnesium alloy is the same as that of the high-toughness and easily soluble magnesium alloy in Example 1; the obtained magnesium alloy is abbreviated as Mg-0.5Zn-3.5Ni-2Gd-1Y-0.12Ga-0.5In alloy and is marked as Sample No. 2.

[0045] The magnesium alloy prepared in Comparative Example 1, as Figure 4 and Figure 5 shown, contains 1 kind of regularly shaped intragranular precipitation phase, that is, the non-oriented MgNi phase; this sample also contains irregularly shaped grain boundary compounds, that is, MgNi compound, MgGa compound, and MgIn compound. In addition, as Figure 6 shown, the Schmid factor of the basal plane slip of this sample is 0.22.

[0046] Comparative Example 2:

[0047] A magnesium alloy, by mass percentage, contains the following parts: 1.5% Zn element, 3.5% Ni element, 2% Gd element, 1% Y element, 0.12% Ga element, 1% In element, and the balance is Mg element.

[0048] The preparation method of this magnesium alloy is the same as that of the high-toughness and easily soluble magnesium alloy in Example 1; the obtained magnesium alloy is abbreviated as Mg-1.5Zn-3.5Ni-2Gd-1Y-0.12Ga-1In alloy and is marked as Sample No. 3.

[0049] The magnesium alloy prepared in Comparative Example 2 does not contain intragranular precipitation phase inside; but this sample contains irregularly shaped grain boundary compounds, that is, MgNi compound, MgGa, and MgIn compounds. In addition, the Schmid factor of the basal plane slip of this sample is 0.38.

[0050] The three magnesium alloys prepared in Example 1, Comparative Example 1, and Comparative Example 2 were subjected to unidirectional tensile tests at room temperature and water solubility tests at room temperature, and the results are shown in Table 1.

[0051] Table 1 Performance test results of magnesium alloys

[0052]

[0053] As can be seen from Table 1, Sample No. 1 has high strength, high elongation rate and high dissolution rate at the same time; although Sample No. 2 can react with water, the Zn content is insufficient, resulting in no MgZn phase generated inside the sample, making it difficult to achieve precipitation strengthening and thus insufficient strength; for Sample No. 3, due to the excessive total amount of Ga and In, the number of grain boundary compounds is too large, which not only induces brittle fracture but also consumes Mg atoms and inhibits the precipitation of MgZn and MgNi phases.

[0054] Example 2:

[0055] A high-toughness and easily soluble magnesium alloy of the present invention, by mass percentage, comprises the following components: 6% Zn element, 2% Ni element, 2% Gd element, 0.05% Ga element, 0.2% In element, and the balance is Mg element.

[0056] A preparation method of the high-toughness and easily soluble magnesium alloy of this example includes the following steps:

[0057] S1. According to the mass percentages of the components in the magnesium alloy, weigh the required raw materials, mix them evenly, melt, refine, and cast to obtain an ingot.

[0058] S2. Perform homogenization treatment on the ingot, that is, keep it at 360 °C for 48 hours.

[0059] S3. Perform hot deformation on the homogenized ingot, that is, perform one-pass extrusion deformation, the extrusion temperature is 350 °C, and the single-pass deformation amount is 90%.

[0060] S4. Perform aging treatment on the extruded material, that is, keep it at 170 °C for 48 hours to obtain a high-toughness and easily soluble magnesium alloy, simply referred to as Mg-6Zn-2Ni-2Gd-0.05Ga-0.2In alloy, marked as Sample No. 4.

[0061] The high-toughness and easily soluble magnesium alloy prepared in this example contains 3 kinds of intragranular precipitation phases with regular shapes inside, namely the basal-plane-oriented MgZn phase, the prismatic-plane-oriented MgZn phase, and the non-oriented MgNi phase; the sample also contains irregularly shaped grain boundary compounds, namely MgNi compounds, MgGa and MgIn compounds; at the same time, the Schmid factor of basal-plane slip of this sample is 0.39.

[0062] Example 3:

[0063] A high-toughness and easily soluble magnesium alloy of the present invention, by mass percentage, comprises the following components: 6% Zn element, 2% Ni element, 2% Gd element, 2% Y element, 0.6% Ga element, 0.1% In element, and the balance is Mg element.

[0064] A preparation method of the high-toughness and easily-soluble magnesium alloy of this embodiment is the same as that of the high-toughness and easily-soluble magnesium alloy in Embodiment 2; the obtained magnesium alloy is abbreviated as Mg-6Zn-2Ni-2Gd-2Y-0.6Ga-0.1In alloy and is marked as Sample No. 5.

[0065] The high-toughness and easily-soluble magnesium alloy obtained in this embodiment contains 3 kinds of regularly-shaped intragranular precipitation phases inside, namely the basal-plane-oriented MgZn phase, the prismatic-plane-oriented MgZn phase, and the non-oriented MgNi phase; this sample also contains irregularly-shaped grain boundary compounds inside, namely MgGdZn, MgYZn, MgNi, MgGdNi, MgYNi, MgGa, and MgIn compounds; meanwhile, the Schmid factor of basal-plane slip of this sample is 0.43.

[0066] Embodiment 4:

[0067] A high-toughness and easily-soluble magnesium alloy of the present invention has the same composition as that of the high-toughness and easily-soluble magnesium alloy in Embodiment 2.

[0068] A preparation method of the high-toughness and easily-soluble magnesium alloy of this embodiment includes:

[0069] S1. Weigh the required raw materials according to the mass percentages of each component in the magnesium alloy, mix them evenly, melt, refine, and cast to obtain an ingot.

[0070] S2. Perform homogenization treatment on the ingot, that is, keep it at 360 °C for 48 hours.

[0071] S3. Perform hot deformation on the homogenized ingot, that is, perform one-pass extrusion deformation, the extrusion temperature is 400 °C, and the deformation amount of a single pass is 90%.

[0072] S4. Perform aging treatment on the extruded material, that is, keep it at 210 °C for 48 hours to obtain a high-toughness and easily-soluble magnesium alloy, abbreviated as Mg-6Zn-2Ni-2Gd-0.05Ga-0.2In alloy and marked as Sample No. 6.

[0073] The high-toughness and easily-soluble magnesium alloy obtained in this embodiment contains 3 kinds of regularly-shaped intragranular precipitation phases inside, namely the basal-plane-oriented MgZn phase, the prismatic-plane-oriented MgZn phase, and the non-oriented MgNi phase; this sample also contains irregularly-shaped grain boundary compounds inside, namely MgNi compounds, MgGa, and MgIn compounds; meanwhile, the Schmid factor of basal-plane slip of this sample is 0.42.

[0074] Comparative Example 3:

[0075] A magnesium alloy, by mass percentage, contains the following components: 6% Zn element, 5.5% Ni element, 2% Gd element, 0.05% Ga element, 0.2% In element, and the balance is Mg element.

[0076] The preparation method of this magnesium alloy is the same as that of the high-toughness and easy-soluble magnesium alloy in Example 2; the obtained magnesium alloy is abbreviated as Mg-6Zn-5.5Ni-2Gd-0.05Ga-0.2In alloy and is marked as Sample No. 7.

[0077] For the magnesium alloy prepared in Comparative Example 3, its sample contains two types of regularly shaped intragranular precipitation phases inside, namely the MgZn phase with a columnar orientation and the MgNi phase without orientation; the sample also contains irregularly shaped grain boundary compounds inside, namely MgGdNi compounds, MgNi compounds, MgGa, and MgIn compounds, and the intragranular precipitation phases also contain irregularly shaped MgNi compounds; at the same time, the basal plane slip Schmid factor of this sample is 0.41.

[0078] Comparative Example 4:

[0079] A magnesium alloy, by mass percentage, contains the following components: 6% Zn element, 2% Ni element, 10% Gd element, 0.05% Ga element, 0.2% In element, and the balance is Mg element.

[0080] The preparation method of this magnesium alloy is the same as that of the high-toughness and easy-soluble magnesium alloy in Example 2; the obtained magnesium alloy is abbreviated as Mg-6Zn-2Ni-10Gd-0.05Ga-0.2In alloy and is marked as Sample No. 8.

[0081] For the magnesium alloy prepared in Comparative Example 4, its sample contains three types of regularly shaped intragranular precipitation phases inside, namely the MgGd and MgZn phases with a columnar orientation and the MgNi phase without orientation; the sample also contains a small amount of irregularly shaped grain boundary compounds inside, namely MgIn compounds; at the same time, the basal plane slip Schmid factor of this sample is 0.47.

[0082] The five magnesium alloys prepared in Example 2, Example 3, Example 4, Comparative Example 3, and Comparative Example 4 were subjected to uniaxial tensile tests at room temperature and water solubility tests at room temperature, and the results are shown in Table 2.

[0083] Table 2 Performance test results of magnesium alloys

[0084]

[0085]

[0086] As can be seen from Table 2, Sample No. 4 has high strength, high elongation and high dissolution rate at the same time. Compared with Sample No. 4, the elongation of Sample No. 5 decreases because the total amount of Gd and Y is relatively high, and MgGdZn, MgYZn, MgGdNi and MgYNi compounds are formed at the grain boundaries, which to a certain extent damages the elongation of this sample. Compared with Sample No. 4, the tensile strength, yield strength and elongation of Sample No. 6 decrease because both the deformation temperature and the aging temperature are relatively high, which coarsens the precipitation phase and causes a slight decrease in strength and elongation. In Sample No. 7, due to the excessive Ni content, the formation of basal-oriented MgZn phase is inhibited, and at the same time, excessive MgNi compounds also induce brittle fracture of the sample. In Sample No. 8, due to the excessive Gd content, a large amount of intragranular MgGd phase is generated, consuming Mg atoms, inhibiting the formation of basal-oriented MgZn phase, MgNi compounds, MgGdNi compounds and MgGa compounds in the grain boundary, and at the same time interrupting the reaction of the sample with water.

[0087] Example 5:

[0088] A high-toughness and easily soluble magnesium alloy of the present invention contains the following components by mass percentage: 3% Zn element, 2% Ni element, 3% Gd element, 0.9% In element, and the balance is Mg element.

[0089] A preparation method of the high-toughness and easily soluble magnesium alloy of this example includes the following steps:

[0090] S1. Weigh the required raw materials according to the mass percentages of the components in the magnesium alloy, mix them evenly, melt, refine and cast to obtain an ingot.

[0091] S2. Perform homogenization treatment on the ingot, that is, keep it at 410 °C for 24 hours.

[0092] S3. Perform hot deformation on the homogenized ingot, that is, perform multi-pass forging deformation. The forging temperature is 380 °C, the single-pass deformation amount is 40%, and the total deformation amount is 87%.

[0093] S4. Perform aging treatment on the forged material, that is, keep it at 210 °C for 60 hours to obtain a high-toughness and easily soluble magnesium alloy, simply referred to as Mg-3Zn-2Ni-3Gd-0.9In alloy, marked as Sample No. 9.

[0094] The high-toughness and easily soluble magnesium alloy prepared in this example contains 3 kinds of intragranular precipitation phases with regular shapes, namely basal-oriented MgZn phase, prismatic-oriented MgZn phase, and non-oriented MgNi phase; the sample also contains irregularly shaped grain boundary compounds, namely MgNi compounds and MgIn compounds; at the same time, the Schmid factor of basal slip of this sample is 0.32.

[0095] Example 6:

[0096] A high-toughness and easily soluble magnesium alloy of the present invention has the same composition as the high-toughness and easily soluble magnesium alloy in Example 5.

[0097] A preparation method of the high-toughness and easily soluble magnesium alloy of this example includes the following steps:

[0098] S1. Weigh the required raw materials according to the mass percentages of the components in the magnesium alloy, mix them evenly, melt, refine, and cast to obtain an ingot.

[0099] S2. Perform homogenization treatment on the ingot, that is, keep it at 410 °C for 24 hours.

[0100] S3. Perform hot deformation on the homogenized ingot, that is, perform multi-pass forging deformation. The forging temperature is 350 °C, the single-pass deformation amount is 40%, and the total deformation amount is 87%.

[0101] S4. Perform aging treatment on the forged material, that is, keep it at 210 °C for 60 hours to obtain a high-toughness and easily soluble magnesium alloy, simply referred to as Mg-3Zn-2Ni-3Gd-0.9In alloy, marked as Sample No. 10.

[0102] The high-toughness and easily soluble magnesium alloy prepared in this example contains 3 kinds of intragranular precipitation phases with regular shapes inside, namely the basal-plane-oriented MgZn phase, the prismatic-plane-oriented MgZn phase, and the non-oriented MgNi phase; the sample also contains irregular-shaped grain boundary compounds inside, namely MgNi compounds and MgIn compounds; at the same time, the Schmid factor of basal-plane slip of this sample is 0.27.

[0103] Comparative Example 5:

[0104] A magnesium alloy has the same composition as the high-toughness and easily soluble magnesium alloy in Example 5.

[0105] The preparation method of this magnesium alloy includes the following steps:

[0106] S1. Weigh the required raw materials according to the mass percentages of the components in the magnesium alloy, mix them evenly, melt, refine, and cast to obtain an ingot.

[0107] S2. Perform homogenization treatment on the ingot, that is, keep it at 410 °C for 24 hours.

[0108] S3. Perform hot deformation on the homogenized ingot, that is, perform one-pass forging deformation. The forging temperature is 450 °C, and the single-pass deformation amount is 40%.

[0109] S4. Age the forged material, that is, hold it at 210 °C for 60 hours to obtain a magnesium alloy, simply referred to as Mg-3Zn-2Ni-3Gd-0.9In alloy, marked as Sample No. 11.

[0110] The magnesium alloy prepared in Comparative Example 5 contains two kinds of intragranular precipitation phases with regular shapes, namely columnar-oriented MgZn phase and non-oriented MgNi phase; the sample also contains irregular-shaped grain boundary compounds, namely MgNi compound and MgIn compound; meanwhile, the Schmid factor of basal plane slip of this sample is 0.23.

[0111] Conduct unidirectional tensile tests and water solubility tests at room temperature on the three kinds of magnesium alloys prepared in Example 5, Example 6, and Comparative Example 5. The results are shown in Table 3.

[0112] Table 3 Performance test results of magnesium alloys

[0113]

[0114] As can be seen from Table 3, Sample No. 9 has high strength, high elongation, and high dissolution rate at the same time; compared with Sample No. 9, the tensile strength, yield strength, elongation, and dissolution rate of Sample No. 10 have decreased. The reason is that: due to the low forging temperature, the Schmid factor of basal plane slip decreases and the elongation decreases, and finally the tensile strength cannot reach the ideal value; for Sample No. 11, due to the too high forging temperature and insufficient deformation, the number of precipitation phases and compounds is small, resulting in a simultaneous decrease in strength and dissolution rate.

[0115] Example 7:

[0116] A high-toughness and easy-soluble magnesium alloy of the present invention contains the following components by mass percentage: 5% Zn element, 1% Ni element, 1% Y element, 0.2% Ga element, 0.2% In element, and the balance is Mg element.

[0117] A preparation method of the high-toughness and easy-soluble magnesium alloy of this example includes the following steps:

[0118] S1. Weigh the required raw materials according to the mass percentages of the components in the magnesium alloy, mix them evenly, melt, refine, and cast to obtain an ingot.

[0119] S2. Perform homogenization treatment on the ingot, that is, hold it at 400 °C for 24 hours.

[0120] S3. Perform hot deformation on the homogenized ingot, that is, perform two-pass forging deformation. The forging temperature is 330 °C, and the single-pass deformation amounts are 50% and 40% respectively, and the total deformation amount is 70%.

[0121] S4. Age the forged material, i.e., hold it at 210 °C for 12 hours, to obtain a high-toughness and easily soluble magnesium alloy, simply referred to as Mg-5Zn-1Ni-1Y-0.2Ga-0.2In alloy, marked as Sample No. 12.

[0122] The high-toughness and easily soluble magnesium alloy prepared in this example contains 3 types of intragranular precipitation phases with regular shapes inside, namely the basal-plane-oriented MgZn phase, the prismatic-plane-oriented MgZn phase, and the non-oriented MgNi phase; the sample also contains irregularly shaped grain boundary compounds inside, namely MgNi compounds, MgGa, and MgIn compounds; meanwhile, the Schmid factor of basal-plane slip of this sample is 0.31.

[0123] Comparative Example 6:

[0124] A magnesium alloy has the same composition as the high-toughness and easily soluble magnesium alloy in Example 7.

[0125] The preparation method of this magnesium alloy includes the following steps:

[0126] S1. Weigh the required raw materials according to the mass percentages of each component in the magnesium alloy, mix them evenly, melt, refine, and cast to obtain an ingot.

[0127] S2. Perform homogenization treatment on the ingot, i.e., hold it at 480 °C for 12 hours;

[0128] S3. Perform hot deformation on the homogenized ingot, i.e., perform two-pass forging deformation, the forging temperature is 330 °C, the deformation amount of a single pass is 20%, and the total deformation amount is 36%.

[0129] S4. Age the forged material, i.e., hold it at 210 °C for 12 hours, to obtain a magnesium alloy, simply referred to as Mg-5Zn-1Ni-1Y-0.2Ga-0.2In alloy, marked as Sample No. 13.

[0130] The magnesium alloy prepared in Comparative Example 6 contains 2 types of intragranular precipitation phases with regular shapes inside, namely the prismatic-plane-oriented MgZn phase and the non-oriented MgNi phase; the sample also contains irregularly shaped grain boundary compounds inside, namely MgNi compounds, MgGa, and MgIn compounds; meanwhile, the Schmid factor of basal-plane slip of this sample is 0.23.

[0131] Comparative Example 7:

[0132] A magnesium alloy contains the following components by mass percentage: 5% Zn element, 0.2% Ni element, 1% In element, and the balance is Mg element.

[0133] The preparation method of this magnesium alloy is the same as that of the high-toughness and easy-to-dissolve magnesium alloy in Example 7; the obtained magnesium alloy is abbreviated as Mg-5Zn-0.2Ni-1In alloy and labeled as Sample No. 14.

[0134] The magnesium alloy prepared in Comparative Example 7 contains two types of regularly shaped intragranular precipitation phases inside, namely the basal-plane-oriented MgZn phase and the prismatic-plane-oriented MgZn phase; the sample also contains irregularly shaped grain boundary compounds inside, namely MgIn compounds; at the same time, the Schmid factor of basal-plane slip of this sample is 0.21.

[0135] The three magnesium alloys prepared in Example 7, Comparative Example 6, and Comparative Example 7 were subjected to uniaxial tensile tests at room temperature and water solubility tests at room temperature, and the results are shown in Table 4.

[0136] Table 4 Performance test results of magnesium alloys

[0137]

[0138] As can be seen from Table 4, Sample No. 12 has high strength, high elongation, and high dissolution rate at the same time; for Sample No. 13, due to the too high homogenization temperature and too small deformation amount, the grain size is coarse and it is difficult to generate basal-plane-oriented MgZn phase, resulting in insufficient strength and a decrease in dissolution rate finally; for Sample No. 14, due to insufficient Ni content and the absence of Gd and Y elements, the dissolution rate and strength decrease simultaneously.

[0139] The above are only the preferred embodiments of the present invention and do not impose any formal restrictions on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above, or modify it into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A high-toughness and easily soluble magnesium alloy, characterized in that, by mass percentage, it contains the following components: 1% - 6% of Zn element, 1% - 4% of Ni element, 0.2% - 4% of A element, 0.2% - 1% of B element, and the balance is Mg element; the A element is at least one of Gd element and Y element, and the B element is at least one of Ga element and In element; the high-toughness and easily soluble magnesium alloy contains 3 kinds of intragranular precipitation phases with regular shapes, and the intragranular precipitation phases are basal-plane-oriented MgZn phase, prism-plane-oriented MgZn phase, and non-oriented MgNi phase; when the A element is Gd element, the intragranular precipitation phase and the grain boundary compound do not contain Gd element; when the A element is Y element, the intragranular precipitation phase and the grain boundary compound do not contain Y element; when the A element is Gd element and Y element, the intragranular precipitation phase and the grain boundary compound do not contain Gd element and Y element.

2. The high-toughness and easily soluble magnesium alloy according to claim 1, characterized in that, the high-toughness and easily soluble magnesium alloy contains irregularly shaped grain boundary compounds. When the B element is Ga element, the grain boundary compounds are MgNi compound and MgGa compound; when the B element is In element, the grain boundary compounds are MgNi compound and MgIn compound; when the B element is Ga element and In element, the grain boundary compounds are MgNi compound, MgGa compound, and MgIn compound.

3. The high-toughness and easily soluble magnesium alloy according to claim 1, characterized in that, when the content of Zn element is 1% - 4%, the content of A element is 2% - 4%, and the content of B element is 0.6% - 1%; when the content of Zn element is 4% - 6%, the content of A element is 0.2% - 2%, and the content of B element is 0.2% - 0.6%.

4. The high-toughness and easily soluble magnesium alloy according to claim 1, characterized in that, when the B element is Ga element and In element, the content of Ga element ≤ the content of In element.

5. The high-toughness and easily soluble magnesium alloy according to any one of claims 1 - 4, characterized in that, the basal-plane slip Schmid factor of the high-toughness and easily soluble magnesium alloy is 0.25 - 0.

45.

6. The high-toughness and easily soluble magnesium alloy according to claim 5, characterized in that, the basal-plane slip Schmid factor of the high-toughness and easily soluble magnesium alloy is 0.3 - 0.

4.

7. A preparation method of a high-toughness and easily soluble magnesium alloy, characterized in that, it includes the following steps: S1. According to the mass percentages of the components in the magnesium alloy, weigh the required raw materials, mix them evenly, melt, refine, and cast to obtain an ingot; the magnesium alloy, by mass percentage, contains the following components: 1% - 6% of Zn element, 1% - 4% of Ni element, 0.2% - 4% of A element, 0.2% - 1% of B element, and the balance is Mg element; the A element is at least one of Gd element and Y element, and the B element is at least one of Ga element and In element; S2. Homogenize the ingot; the temperature of the homogenization treatment is 360°C to 450°C, and the time of the homogenization treatment is 6 hours to 48 hours; S3. Perform hot deformation on the homogenized material; the temperature of the hot deformation is 330°C to 420°C, and the total deformation amount of the hot deformation is 70% to 90%; S4. Perform aging treatment on the hot-deformed material; the temperature of the aging treatment is 170°C to 220°C, and the time of the aging treatment is 6 hours to 96 hours.

8. The method for preparing a high-toughness and easily soluble magnesium alloy according to claim 7, characterized in that, when the content of Zn element is 1% to 4%, the temperature of the hot deformation is 370°C to 420°C, and the temperature of the aging treatment is 200°C to 220°C; when the content of Zn element is 4% to 6%, the temperature of the hot deformation is 330°C to 370°C, and the temperature of the aging treatment is 170°C to 200°C.

9. The method for preparing a high-toughness and easily soluble magnesium alloy according to claim 7 or 8, characterized in that, in step S3, the hot deformation is at least one of extrusion, forging and rolling; the deformation amount of a single pass of the extrusion is 70% to 90%, the deformation amount of a single pass of the forging is 30% to 50%, and the deformation amount of a single pass of the rolling is 10% to 40%.

Images