Rare earth magnesium alloy based on high temperature and high pressure hydrogenation and preparation method thereof

Abstract

The present invention provides a rare earth magnesium alloy based on high temperature and high pressure hydrogenation and a preparation method thereof, belonging to the technical field of alloy materials. The method of regulating the structure of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation of the present invention greatly improves the plasticity of the rare earth magnesium alloy, and can also achieve similar structures in other high gadolinium (Gd) and high yttrium (Y) systems, providing a unique magnesium alloy plasticization idea, and providing more room for regulating the mechanical properties of such rare earth alloys through other deformation processes in the future. In addition, the rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention can be used for neutron shielding, and is a material with integrated structural and functional design in the nuclear energy field and the space field.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to a rare earth magnesium alloy based on high temperature and high pressure hydrogenation and a preparation method thereof. Background Art

[0002] As the lightest metal structural material currently available, magnesium alloy has broad application prospects in aerospace, national defense, military industry, 3C digital and other fields.

[0003] At present, many high-strength magnesium alloys are being researched and applied around the addition of two rare earth elements, gadolinium (Gd) and yttrium (Y). However, magnesium alloys with these two rare earth elements have the disadvantage of poor ductility in both cast and deformed forms (extrusion, rolling, rotary forging, etc.). The main reason is that the hard and brittle second phase containing large rare earth elements in the alloy, such as Mg 24 (Gd, Y)5, and Al2(Gd, Y) generated by adding aluminum (Al) elements, are more likely to form cracks near them, which reduces the plasticity of the alloy. Therefore, the demand for high-plasticity rare earth magnesium alloy materials and their preparation methods is an important issue that needs to be solved urgently in the industry.

[0004] The method of regulating the microstructure of rare earth magnesium alloy based on high temperature and high pressure hydrogenation in the present invention greatly improves the plasticity of rare earth magnesium alloy, and can also achieve similar microstructure in other high gadolinium (Gd) and high yttrium (Y) systems, providing a unique idea for plasticizing magnesium alloys and providing more room for regulating the mechanical properties of such rare earth alloys through other deformation processes in the future.

[0005] In addition, current traditional neutron shielding materials generally have the problems of heavy weight (such as boron steel, boron aluminum alloy), poor strength and ductility (such as borates, lithium hydride), etc. The present invention optimizes the mechanical properties of the material through hydrogenation-deformation processing, and at the same time, due to the presence of hydrogen (H) and gadolinium (Gd) in the material, it has certain neutron shielding performance.

[0006] The rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention can be used for neutron shielding while having certain mechanical properties, and can be used as a material for structural and functional integrated design in the nuclear energy field and the space field. Summary of the invention

[0007] The present invention provides a rare earth magnesium alloy based on high temperature and high pressure hydrogenation and a preparation method thereof, which are used to solve the technical problem of low plasticity of rare earth magnesium alloy in the prior art.

[0008] On the one hand, the present invention provides a rare earth magnesium alloy based on high temperature and high pressure hydrogenation, wherein the elements and mass percentages in the rare earth magnesium alloy are: gadolinium 0~23.5wt%, yttrium 0~12.5wt%, aluminum 0.1~3wt%, and the balance is magnesium and unavoidable impurities, and the rare earth magnesium alloy based on high temperature and high pressure hydrogenation contains at least one of gadolinium or yttrium.

[0009] According to a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the unavoidable impurities and their mass percentages are: iron ≤ 0.01wt%, nickel ≤ 0.0054wt%, and copper ≤ 0.005wt%.

[0010] On the other hand, the present invention also provides a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation, comprising the following steps:

[0011] (1) According to the element composition of the rare earth magnesium alloy, pure magnesium, pure aluminum, Mg-30Gd master alloy and Mg-30Y master alloy are weighed and preheated;

[0012] (2) Under the protection of the mixed gas, the furnace temperature is increased to melt the pure magnesium to obtain molten magnesium;

[0013] (3) Under the protection of the mixed gas, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added to the molten magnesium in sequence, and the scum is removed and stirred, and the mixture is kept warm to obtain a mixed melt;

[0014] (4) Under the protection of the mixed gas, the furnace temperature is lowered, the surface slag is removed, and a refining agent is added to the mixed melt to obtain a rare earth magnesium alloy melt;

[0015] (5) Under the protection of the mixed gas, the furnace temperature is raised, the furnace is kept still to keep warm, and the surface slag is removed to obtain a purified rare earth magnesium alloy melt;

[0016] (6) Under the protection of the mixed gas, the furnace temperature is lowered, the purified rare earth magnesium alloy melt is cooled to the casting temperature, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a preheated mold to obtain a rare earth magnesium alloy ingot;

[0017] (7) The rare earth magnesium alloy ingot is cut to remove the shrinkage and surface oxide scale, and is placed in a hydrogenation reactor for hydrogenation treatment to obtain a rare earth magnesium alloy based on high temperature and high pressure hydrogenation.

[0018] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the mixed gas in step (2), step (3), step (4) and step (5) is a mixed gas of SF6:CO2=1:48~52.

[0019] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the temperature of the preheating treatment in step (1) is 190-210°C, the furnace temperature in step (2) is 730-750°C, the furnace temperature in step (3) is 750-770°C, the furnace temperature in step (4) is 730-750°C, the furnace temperature in step (5) is 750-770°C, the furnace temperature in step (6) is 720-740°C, the temperature of the purified rare earth magnesium alloy melt during pouring is 710-730°C, the mold preheating temperature is 190-210°C, the temperature of the hydrogenation treatment in step (7) is 480-520°C, the pressure of the hydrogenation treatment is 0.5-10MPa, and the time of the hydrogenation treatment is 35-45h.

[0020] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the time of the heat preservation treatment in the step (3) is 10 to 20 minutes.

[0021] According to the method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the time for standing and keeping warm in step (5) is 10 to 15 minutes.

[0022] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the refining agent in step (4) is JDMJ, and the amount of the refining agent is 1.5-2.5% of the total mass of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation;

[0023] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the refining agent in the step (4) is added three times with an interval of 2 to 5 minutes under stirring conditions.

[0024] The rare earth magnesium alloy based on high temperature and high pressure hydrogenation and the preparation method thereof provided by the present invention can refine the originally large rare earth second phase into finer rare earth hydride through the hydrogenation process, so that it can coordinate a larger deformation, solve the technical problems of poor ductility and easy crack generation of rare earth magnesium alloy in the prior art, and achieve the beneficial effect of greatly improving the plasticity of rare earth magnesium alloy. In addition, the rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention can be used for neutron shielding, and is a material with integrated structural and functional design in the nuclear energy field and the space field. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 is a structural representation diagram of Example 4 of the present invention before and after hydrogenation treatment;

[0027] Figure 2 1 is the XRD diagram of Example 4 of the present invention before and after hydrogenation treatment;

[0028] Figure 3 is a detailed characterization diagram of the characteristic hydride in Example 4 of the present invention;

[0029] Figure 4 is a tensile mechanics curve diagram of the magnesium alloy before and after hydrogenation treatment in Example 4 of the present invention;

[0030] Figure 5 This is a performance comparison diagram of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation after being processed by different deformation processes provided by the present invention;

[0031] Figure 6 The microstructure diagrams of hydrogenated rare earth magnesium alloys with different hydrogenation treatment process parameters under a scanning electron microscope provided by the present invention, (a) is the structure under a scanning electron microscope of Example 4, and (b) is the structure under a scanning electron microscope of Example 5;

[0032] Figure 7 It is a Monte Carlo simulation (MCNP) neutron shielding performance diagram of pure aluminum, pure magnesium and Example 4 of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Combine the following Figure 1-Figure 7 The present invention is described.

[0035] Figure 1 It is a structural characterization diagram of Example 4 of the present invention before and after hydrogenation treatment.

[0036] like Figure 1 As shown, from top to bottom are the structures under optical microscopy (OM), scanning electron microscopy (SEM) and phase analysis by electron backscatter diffraction (EBSD). From the EBSD characterization, it can be seen that the green part structure (Mg 24(Gd, Y)5) and the blue part of the structure (Al2(Gd, Y)) completely disappeared, and were replaced by the rare earth hydride (Gd, Y)H2 structure marked in green.

[0037] Figure 2 1 is the XRD diagram of Example 4 of the present invention before and after hydrogenation treatment.

[0038] like Figure 2 As shown, the magnesium alloy is transformed into a hydrogenated state after hydrogenation treatment.

[0039] Figure 3 This is a detailed characterization diagram of the characteristic hydride in Example 4 of the present invention.

[0040] like Figure 3 As shown in the figure, the typical hydrides appearing in the alloy after hydrogenation were characterized, and it was found that the original Al2(Gd,Y) was refined into fine rare earth hydrides with various orientations. The refined structure after hydrogenation treatment made a significant contribution to the plasticity of the alloy, further confirming the phase changes during the hydrogenation treatment.

[0041] Figure 4 It is a tensile mechanics curve diagram of the magnesium alloy before and after hydrogenation treatment in Example 4 of the present invention.

[0042] like Figure 4 As shown in the figure, compared with the alloy before hydrogenation, the plasticity of the alloy after hydrogenation is greatly improved.

[0043] Figure 5 This is a performance comparison chart of rare earth magnesium alloys based on high temperature and high pressure hydrogenation after being processed by different deformation processes provided by an embodiment of the present invention.

[0044] like Figure 5 As shown in the figure, the rare earth magnesium alloy based on high temperature and high pressure hydrogenation was extruded at 375℃ and 1.7mm / s, and then further rotary forged at room temperature and medium temperature forged at 300℃ and 0.005% / s in the extruded state. The mechanical properties were compared with those of the hydrogenated alloy and the cast alloy. It can be seen that different deformation processes can further refine the grains and improve the strength.

[0045] Figure 6 The microstructure diagrams of hydrogenated rare earth magnesium alloys with different hydrogenation treatment process parameters under a scanning electron microscope provided by the present invention, (a) is the structure of Example 4 under a scanning electron microscope, and (b) is the structure of Example 5 under a scanning electron microscope.

[0046] like Figure 6 As shown, Example 4 and Example 5 have the same alloy composition and different hydrogen permeation parameters, and the hydrides in the microstructure are significantly different, and the mechanical properties of Example 4 and Example 5 are different. This shows that different hydrogenation processes can achieve the regulation of the structure and thus affect the mechanical properties of the material.

[0047] Figure 7 It is a Monte Carlo simulation (MCNP) neutron shielding performance diagram of pure aluminum, pure magnesium and Example 4 of the present invention.

[0048] like Figure 7 As shown, pure aluminum and pure magnesium have no shielding effect on neutrons, while Example 4 of the present invention can effectively shield neutrons of 1E-7 MeV and below.

[0049] On the one hand, the present invention provides a rare earth magnesium alloy based on high temperature and high pressure hydrogenation, wherein the elements and mass percentages in the rare earth magnesium alloy are: gadolinium 0-23.5wt%, yttrium 0-12.5wt%, aluminum 0.1-3wt%, and the balance is magnesium and inevitable impurities. The rare earth magnesium alloy based on high temperature and high pressure hydrogenation contains at least one of gadolinium or yttrium, preferably 10-20wt% of gadolinium, 1-10wt% of yttrium, and 0.5-2wt% of aluminum, and further preferably 13-17wt% of gadolinium, 1.5-5wt% of yttrium, and 0.8-1.2wt% of aluminum.

[0050] According to a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the unavoidable impurities and their mass percentages are: iron ≤ 0.01wt%, nickel ≤ 0.0054wt%, and copper ≤ 0.005wt%.

[0051] On the other hand, the present invention also provides a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation, comprising the following steps:

[0052] (1) According to the element composition of the rare earth magnesium alloy, pure magnesium, pure aluminum, Mg-30Gd master alloy and Mg-30Y master alloy are weighed and preheated;

[0053] (2) Under the protection of the mixed gas, the furnace temperature is increased to melt the pure magnesium to obtain molten magnesium;

[0054] (3) Under the protection of the mixed gas, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added to the molten magnesium in sequence, and the surface scum is removed and stirred, and the mixture is kept warm to obtain a mixed melt;

[0055] (4) Under the protection of the mixed gas, the furnace temperature is lowered, the surface slag is removed, and a refining agent is added to the mixed melt to obtain a rare earth magnesium alloy melt;

[0056] (5) Under the protection of the mixed gas, the furnace temperature is raised, the furnace is kept still to keep warm, and the surface slag is removed to obtain a purified rare earth magnesium alloy melt;

[0057] (6) Under the protection of the mixed gas, the furnace temperature is lowered, the purified rare earth magnesium alloy melt is cooled to the casting temperature, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a preheated mold to obtain a rare earth magnesium alloy ingot;

[0058] (7) The rare earth magnesium alloy ingot is cut to remove the shrinkage and surface oxide scale, and is placed in a hydrogenation reactor for hydrogenation treatment to obtain a rare earth magnesium alloy based on high temperature and high pressure hydrogenation.

[0059] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the mixed gas in step (2), step (3), step (4) and step (5) is a mixed gas of SF6:CO2=1:48~52, preferably SF6:CO2=1:49~51, and more preferably SF6:CO2=1:50.

[0060] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the temperature of the preheat treatment in step (1) is 190-210°C, preferably 195-205°C, and more preferably 198-202°C; the furnace temperature in step (2) is 730-750°C, preferably 735-745°C, and more preferably 738-742°C; the furnace temperature in step (3) is 750-770°C, preferably 755-765°C, and more preferably 758-762°C; the furnace temperature in step (4) is 730-750°C, preferably 735-745°C , more preferably 738~742°C; the furnace temperature in step (5) is 750~770°C, preferably 755~765°C, and more preferably 758~762°C; the furnace temperature in step (6) is 720~740°C, preferably 725~735°C, and more preferably 728~732°C. The temperature of the purified rare earth magnesium alloy melt during pouring is 710~730°C, preferably 715~725°C, and more preferably 718~722°C. The mold preheating temperature is 190~210°C, preferably 195~205°C, and more preferably 198~202°C.

[0061] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the time of the heat preservation treatment in step (3) is 10 to 20 minutes, preferably 12 to 18 minutes, and more preferably 14 to 16 minutes.

[0062] According to the method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the time for standing and keeping warm in step (5) is 10 to 15 minutes, preferably 12 to 14 minutes.

[0063] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the refining agent in step (4) is JDMJ, and the amount of the refining agent is 1.5-2.5% of the total mass of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation.

[0064] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the refining agent in the step (4) is added three times with an interval of 2 to 5 minutes under stirring conditions.

[0065] According to a method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation provided by the present invention, the temperature of the hydrogenation treatment in step (7) is 480~520°C, preferably 490~510°C, and more preferably 495~505°C; the pressure of the hydrogenation treatment is 0.5~10MPa, preferably 1~4MPa, and more preferably 2~3MPa; the time of the hydrogenation treatment is 35~45h, preferably 37~43h, and more preferably 39~41h.

[0066] After hydrogen permeation treatment, deformation processes such as medium temperature slow forging, medium temperature slow extrusion, rotary forging, etc. can be carried out according to actual needs to achieve the purpose of further regulating the organization and mechanical properties. The deformation process can still be freely designed according to different needs. After hydrogen permeation treatment, the plasticity of rare earth magnesium alloy is greatly improved, providing processing space for different deformation processes.

[0067] Example 1

[0068] 1684 g of pure magnesium, 91.8 g of pure aluminum, 4000 g of Mg-30Gd master alloy and 860 g of Mg-30Y master alloy were weighed and preheated at 200°C.

[0069] Under the protection condition of SF6:CO2=1:50 mixed gas, the furnace temperature is increased to 740°C, pure magnesium is melted to obtain molten magnesium; then the furnace temperature is increased to 760°C, Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added in sequence, the surface scum is removed and stirred, and the mixed melt is obtained by heat preservation for 15 minutes; the furnace temperature is lowered to 740°C, and under stirring conditions, 2% of the total mass of the rare earth magnesium alloy refining agent JDMJ is added to the mixed melt three times with an interval of 3 minutes to obtain a rare earth magnesium alloy melt; the furnace temperature is increased to 760°C, and the mixture is kept at room temperature for 13 minutes, and the surface scum is removed to obtain a purified rare earth magnesium alloy melt; the furnace temperature is lowered to 730°C, the purified rare earth magnesium alloy melt is cooled to 720°C, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a mold preheated to 200°C to obtain a rare earth magnesium alloy ingot. After testing, the chemical composition of the magnesium alloy ingot is as follows: Gd 15.12 wt%, Y 2.61 wt%, Al 1.18wt%; the inevitable impurities are: Fe 0.0020wt%, Ni 0.001 wt%, Cu 0.0015 wt%, and the balance is Mg.

[0070] The rare earth magnesium alloy ingot was cut to remove the shrinkage and surface oxide scale, placed in a hydrogenation reactor, and hydrogenated at 500℃-2MPa-40h to obtain a rare earth magnesium alloy based on high temperature and high pressure hydrogenation. After testing, the adsorption concentration of hydrogen after hydrogenation was H 0.5193 wt%.

[0071] The rare earth magnesium alloy based on high temperature and high pressure hydrogenation is heated to 375°C and extruded into rods at a rate of 1.7 mm / s.

[0072] According to tests, the tensile strength of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation in this embodiment is 420.0 MPa, and the elongation at break is 1.6%.

[0073] Example 2

[0074] 1684 g of pure magnesium, 91.8 g of pure aluminum, 4000 g of Mg-30Gd master alloy and 860 g of Mg-30Y master alloy were weighed and preheated at 200°C.

[0075] Under the protection condition of SF6:CO2=1:50 mixed gas, the furnace temperature is increased to 740°C, pure magnesium is melted to obtain molten magnesium; then the furnace temperature is increased to 760°C, Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added in sequence, the surface scum is removed and stirred, and the mixed melt is obtained by heat preservation for 15 minutes; the furnace temperature is lowered to 740°C, and under stirring conditions, 2% of the total mass of the rare earth magnesium alloy refining agent JDMJ is added to the mixed melt three times with an interval of 3 minutes to obtain a rare earth magnesium alloy melt; the furnace temperature is increased to 760°C, and the mixture is kept at room temperature for 13 minutes, and the surface scum is removed to obtain a purified rare earth magnesium alloy melt; the furnace temperature is lowered to 730°C, the purified rare earth magnesium alloy melt is cooled to 720°C, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a mold preheated to 200°C to obtain a rare earth magnesium alloy ingot. After testing, the chemical composition of the magnesium alloy ingot is as follows: Gd 15.12 wt%, Y 2.61 wt%, Al 1.18wt%; the inevitable impurities are: Fe 0.0020wt%, Ni 0.001 wt%, Cu 0.0015 wt%, and the balance is Mg.

[0076] The rare earth magnesium alloy ingot was cut to remove the shrinkage and surface oxide scale, placed in a hydrogenation reactor, and hydrogenated at 500℃-2MPa-40h to obtain a rare earth magnesium alloy based on high temperature and high pressure hydrogenation. After testing, the adsorption concentration of hydrogen after hydrogenation was H 0.5193 wt%.

[0077] The rare earth magnesium alloy based on high temperature and high pressure hydrogenation is heated to 375°C, extruded into a rod at a rate of 1.7 mm / s, and then rotary forged at room temperature.

[0078] According to tests, the tensile strength of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation in this embodiment is 413.7 MPa, and the elongation at break is 1.7%.

[0079] Example 3

[0080] 1684 g of pure magnesium, 91.8 g of pure aluminum, 4000 g of Mg-30Gd master alloy and 860 g of Mg-30Y master alloy were weighed and preheated at 200°C.

[0081] Under the protection condition of SF6:CO2=1:50 mixed gas, the furnace temperature is increased to 740°C, pure magnesium is melted to obtain molten magnesium; then the furnace temperature is increased to 760°C, Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added in sequence, the surface scum is removed and stirred, and the mixed melt is obtained by heat preservation for 15 minutes; the furnace temperature is lowered to 740°C, and under stirring conditions, 2% of the total mass of the rare earth magnesium alloy refining agent JDMJ is added to the mixed melt three times with an interval of 3 minutes to obtain a rare earth magnesium alloy melt; the furnace temperature is increased to 760°C, and the mixture is kept at room temperature for 13 minutes, and the surface scum is removed to obtain a purified rare earth magnesium alloy melt; the furnace temperature is lowered to 730°C, the purified rare earth magnesium alloy melt is cooled to 720°C, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a mold preheated to 200°C to obtain a rare earth magnesium alloy ingot. After testing, the chemical composition of the magnesium alloy ingot is as follows: Gd 15.12 wt%, Y 2.61 wt%, Al 1.18wt%; the inevitable impurities are: Fe 0.0020wt%, Ni 0.001 wt%, Cu 0.0015 wt%, and the balance is Mg.

[0082] The rare earth magnesium alloy ingot was cut to remove the shrinkage and surface oxide scale, placed in a hydrogenation reactor, and hydrogenated at 500℃-2MPa-40h to obtain a rare earth magnesium alloy based on high temperature and high pressure hydrogenation. After testing, the adsorption concentration of hydrogen after hydrogenation was H 0.5193 wt%.

[0083] The rare earth magnesium alloy based on high temperature and high pressure hydrogenation was heated to 300°C and forged at a rate of 0.005% / s, with a final deformation of 80%.

[0084] According to tests, the tensile strength of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation in this embodiment is 299.2 MPa, and the elongation at break is 5.1%.

[0085] Example 4

[0086] 1684 g of pure magnesium, 91.8 g of pure aluminum, 4000 g of Mg-30Gd master alloy and 860 g of Mg-30Y master alloy were weighed and preheated at 200°C.

[0087] Under the protection condition of SF6:CO2=1:50 mixed gas, the furnace temperature is increased to 740°C, pure magnesium is melted to obtain molten magnesium; then the furnace temperature is increased to 760°C, Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added in sequence, the surface scum is removed and stirred, and the mixed melt is obtained by heat preservation for 15 minutes; the furnace temperature is lowered to 740°C, and under stirring conditions, 2% of the total mass of the rare earth magnesium alloy refining agent JDMJ is added to the mixed melt three times with an interval of 3 minutes to obtain a rare earth magnesium alloy melt; the furnace temperature is increased to 760°C, and the mixture is kept at room temperature for 13 minutes, and the surface scum is removed to obtain a purified rare earth magnesium alloy melt; the furnace temperature is lowered to 730°C, the purified rare earth magnesium alloy melt is cooled to 720°C, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a mold preheated to 200°C to obtain a rare earth magnesium alloy ingot. After testing, the chemical composition of the magnesium alloy ingot is as follows: Gd 15.20 wt%, Y 2.42 wt%, Al 1.09 wt%; the inevitable impurities are: Fe0.0018 wt%, Ni 0.0013 wt%, Cu 0.0012 wt%, and the balance is Mg.

[0088] The rare earth magnesium alloy ingot was cut to remove the shrinkage and surface oxide scale, placed in a hydrogenation reactor, and hydrogenated at 500℃-2MPa-40h to obtain a rare earth magnesium alloy based on high temperature and high pressure hydrogenation. After testing, the adsorption concentration of hydrogen after hydrogenation was H 0.5193 wt%.

[0089] According to tests, the rare earth magnesium alloy based on high temperature and high pressure hydrogenation in this embodiment has a tensile strength of 193.0 MPa, an elongation at break of 6.6%, and can effectively shield neutrons of 1E-7 MeV and below.

[0090] Example 5

[0091] 1684 g of pure magnesium, 91.8 g of pure aluminum, 4000 g of Mg-30Gd master alloy and 860 g of Mg-30Y master alloy were weighed and preheated at 200°C.

[0092] Under the protection condition of SF6:CO2=1:50 mixed gas, the furnace temperature is increased to 740°C, pure magnesium is melted to obtain molten magnesium; then the furnace temperature is increased to 760°C, Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added in sequence, the surface scum is removed and stirred, and the mixed melt is obtained by heat preservation for 15 minutes; the furnace temperature is lowered to 740°C, and under stirring conditions, 2% of the total mass of the rare earth magnesium alloy refining agent JDMJ is added to the mixed melt three times with an interval of 3 minutes to obtain a rare earth magnesium alloy melt; the furnace temperature is increased to 760°C, and the mixture is kept at room temperature for 13 minutes, and the surface scum is removed to obtain a purified rare earth magnesium alloy melt; the furnace temperature is lowered to 730°C, the purified rare earth magnesium alloy melt is cooled to 720°C, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a mold preheated to 200°C to obtain a rare earth magnesium alloy ingot. After testing, the chemical composition of the magnesium alloy ingot is as follows: Gd 15.20 wt%, Y 2.42 wt%, Al 1.09 wt%; the inevitable impurities are: Fe0.0018 wt%, Ni 0.0013 wt%, Cu 0.0012 wt%, and the balance is Mg.

[0093] The rare earth magnesium alloy ingot was cut to remove the shrinkage and surface oxide scale, placed in a hydrogenation reactor, and hydrogenated at 500℃-4MPa-40h to obtain a rare earth magnesium alloy based on high temperature and high pressure hydrogenation. After testing, the adsorption concentration of hydrogen after hydrogenation was H 0.5779 wt%.

[0094] According to tests, the tensile strength of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation in this embodiment is 179.7 MPa, and the elongation at break is 5.0%.

[0095] Comparative Example 1

[0096] 3090 g of pure magnesium, 3200 g of Mg-30Gd master alloy and 125 g of Mg-30Zr master alloy were weighed and preheated at 200°C.

[0097] Under the protection condition of SF6:CO2=1:50 mixed gas, the furnace temperature is increased to 740°C, pure magnesium is melted to obtain molten magnesium; then the furnace temperature is increased to 760°C, Mg-30Gd master alloy and Mg-30Zr master alloy are added in sequence, and the surface scum is removed after heat preservation for 15 minutes to obtain a mixed melt; the furnace temperature is lowered to 740°C, and under stirring conditions, 2% of the total mass of the rare earth magnesium alloy refining agent JDMJ is added to the mixed melt three times with an interval of 3 minutes to obtain a rare earth magnesium alloy melt; the furnace temperature is increased to 760°C, and the mixture is kept at room temperature for 13 minutes, and the surface scum is removed to obtain a purified rare earth magnesium alloy melt; the furnace temperature is lowered to 730°C, the purified rare earth magnesium alloy melt is cooled to 720°C, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a mold preheated to 200°C to obtain a rare earth magnesium alloy ingot. After testing, the chemical composition of the magnesium alloy ingot is as follows: Gd 11.92 wt%, Zr 0.42 wt%; the inevitable impurities are: Fe 0.0012wt%, Ni 0.0008 wt%, Cu0.0006 wt%, and the balance is Mg.

[0098] The rare earth magnesium alloy ingot was cut to remove the shrinkage and surface oxide scale, placed in a hydrogenation reactor, and hydrogenated at 500℃-2MPa-40h to obtain a rare earth magnesium alloy based on high temperature and high pressure hydrogenation. After testing, the adsorption concentration of hydrogen after hydrogenation was H 0.5021 wt%.

[0099] According to the test, the tensile strength of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation in this comparative example is 203.3 MPa, and the elongation at break is 4.4%.

[0100] Comparative Example 2

[0101] The magnesium alloy ingot was prepared by the same preparation method as in Comparative Example 1, and no hydrogenation treatment was performed. The chemical composition of the magnesium alloy ingot is as follows: Gd 11.92 wt%, Zr 0.42 wt%; the inevitable impurities are: Fe 0.0012 wt%, Ni 0.0008 wt%, Cu 0.0006 wt%, and the balance is Mg.

[0102] According to the test, the tensile strength of the magnesium alloy ingot in this comparative example is 178.41 MPa, and the elongation at break is 3.95%.

[0103] Comparative Example 3

[0104] The same preparation method as in Example 4 was used to prepare the magnesium alloy ingot, and no hydrogenation treatment was performed. The chemical composition of the magnesium alloy ingot was as follows: Gd 15.20 wt%, Y 2.42 wt%, Al 1.09 wt%; the inevitable impurities were: Fe 0.0018 wt%, Ni 0.0013 wt%, Cu 0.0012 wt%, and the balance was Mg.

[0105] According to the test, the tensile strength of the magnesium alloy ingot in this comparative example is 204.90 MPa, and the elongation at break is 0.88%.

[0106] It can be concluded from the above embodiments and comparative examples that embodiment 4 and embodiment 5 have the same alloy components, different hydrogenation treatment parameters, and the hydrides in the microstructure have significant differences, and the mechanical properties are different. Embodiments 1 to 4 have the same alloy components, the same hydrogenation treatment parameters, and different deformation processes, and the mechanical properties achieved are different. It can be seen that different deformation processes after hydrogenation treatment can further regulate the organization and mechanical properties. Embodiment 4 and comparative example 1 have different alloy components, the same hydrogenation treatment parameters, and the mechanical properties achieved are different. It can be seen that the alloy composition also has a significant effect on the mechanical properties of the alloy.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rare earth magnesium alloy based on high temperature and high pressure hydrogenation, characterized in that: The elements and mass percentages in the rare earth magnesium alloy are: Gadolinium 0~23.5wt%; Yttrium 0~12.5wt%; Aluminum 0.1~3wt%; The balance is magnesium and unavoidable impurities; The rare earth magnesium alloy based on high temperature and high pressure hydrogenation contains at least one of gadolinium or yttrium; The unavoidable impurities and their mass percentages are: Iron ≤ 0.01wt%; Nickel ≤ 0.0054wt%; Copper ≤ 0.005wt%; The method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation comprises the following steps: (1) According to the element composition of the rare earth magnesium alloy, pure magnesium, pure aluminum, Mg-30Gd master alloy and Mg-30Y master alloy are weighed and preheated; (2) Under the protection of the mixed gas, the furnace temperature is increased to melt the pure magnesium to obtain molten magnesium; (3) Under the protection of the mixed gas, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added to the molten magnesium in sequence, and the scum is removed and stirred, and the mixture is kept warm to obtain a mixed melt; (4) Under the protection of the mixed gas, the furnace temperature is lowered, the surface slag is removed, and a refining agent is added to the mixed melt to obtain a rare earth magnesium alloy melt; (5) Under the protection of the mixed gas, the furnace temperature is raised, the furnace is kept still to keep warm, and the surface slag is removed to obtain a purified rare earth magnesium alloy melt; (6) Under the protection of the mixed gas, the furnace temperature is lowered, the purified rare earth magnesium alloy melt is cooled to the casting temperature, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a preheated mold to obtain a rare earth magnesium alloy ingot; (7) cutting off the shrinkage and surface oxide scale of the purified rare earth magnesium alloy ingot, placing it in a hydrogenation reactor for hydrogenation treatment, and obtaining a rare earth magnesium alloy based on high temperature and high pressure hydrogenation; The temperature of the preheating treatment in step (1) is 190-210°C; In step (2), the furnace temperature is 730-750°C; In step (3), the furnace temperature is 750-770°C; In step (4), the furnace temperature is 730-750°C; In step (5), the furnace temperature is 750-770°C; In step (6), the furnace temperature is 720-740°C, the temperature of the purified rare earth magnesium alloy melt during pouring is 710-730°C, and the mold preheating temperature is 190-210°C; In step (7), the temperature of the hydrogenation treatment is 480-520° C., the pressure of the hydrogenation treatment is 0.5-10 MPa, and the time of the hydrogenation treatment is 35-45 h. The heat preservation time in step (3) is 10 to 20 minutes; The time for standing and keeping warm in step (5) is 10 to 15 minutes.

2. A method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation, characterized in that: The following steps are involved: (1) According to the element composition of the rare earth magnesium alloy, pure magnesium, pure aluminum, Mg-30Gd master alloy and Mg-30Y master alloy are weighed and preheated; (2) Under the protection of the mixed gas, the furnace temperature is increased to melt the pure magnesium to obtain molten magnesium; (3) Under the protection of the mixed gas, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and pure aluminum are added to the molten magnesium in sequence, and the scum is removed and stirred, and the mixture is kept warm to obtain a mixed melt; (4) Under the protection of the mixed gas, the furnace temperature is lowered, the surface slag is removed, and a refining agent is added to the mixed melt to obtain a rare earth magnesium alloy melt; (5) Under the protection of the mixed gas, the furnace temperature is raised, the furnace is kept still to keep warm, and the surface slag is removed to obtain a purified rare earth magnesium alloy melt; (6) Under the protection of the mixed gas, the furnace temperature is lowered, the purified rare earth magnesium alloy melt is cooled to the casting temperature, the surface scum is removed, and the purified rare earth magnesium alloy melt is cast into a preheated mold to obtain a rare earth magnesium alloy ingot; (7) cutting off the shrinkage and surface oxide scale of the purified rare earth magnesium alloy ingot, placing it in a hydrogenation reactor for hydrogenation treatment, and obtaining a rare earth magnesium alloy based on high temperature and high pressure hydrogenation; The temperature of the preheating treatment in step (1) is 190-210°C; In step (2), the furnace temperature is 730-750°C; In step (3), the furnace temperature is 750-770°C; In step (4), the furnace temperature is 730-750°C; In step (5), the furnace temperature is 750-770°C; In step (6), the furnace temperature is 720-740°C, the temperature of the purified rare earth magnesium alloy melt during pouring is 710-730°C, and the mold preheating temperature is 190-210°C; In step (7), the temperature of the hydrogenation treatment is 480-520° C., the pressure of the hydrogenation treatment is 0.5-10 MPa, and the time of the hydrogenation treatment is 35-45 h. The heat preservation time in step (3) is 10 to 20 minutes; The time of standing and keeping warm in step (5) is 10 to 15 minutes; The elements and mass percentages in the rare earth magnesium alloy are: Gadolinium 0~23.5wt%; Yttrium 0~12.5wt%; Aluminum 0.1~3wt%; The balance is magnesium and unavoidable impurities; The rare earth magnesium alloy based on high temperature and high pressure hydrogenation contains at least one of gadolinium or yttrium; The unavoidable impurities and their mass percentages are: Iron ≤ 0.01wt%; Nickel ≤ 0.0054wt%; Copper ≤0.005wt%.

3. The method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation according to claim 2, characterized in that: The mixed gas in step (2), step (3), step (4) and step (5) is a mixed gas of SF6:CO2=1:48~52.

4. The method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation according to claim 2, characterized in that: In the step (4), the refining agent is JDMJ, and the amount of the refining agent is 1.5-2.5% of the total mass of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation.

5. The method for preparing a rare earth magnesium alloy based on high temperature and high pressure hydrogenation according to claim 2, characterized in that: The refining agent in step (4) is added three times with an interval of 2 to 5 minutes under stirring.

6. Application of the rare earth magnesium alloy based on high temperature and high pressure hydrogenation as claimed in claim 1 in neutron shielding.

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