A porous structure rare earth aluminum master alloy additive and preparation method thereof

Abstract

The present invention discloses a porous structure rare earth aluminum master alloy additive and a preparation method thereof, wherein the porous structure rare earth aluminum master alloy additive comprises rare earth and aluminum, and the rare earth aluminum master alloy additive has a porous structure; wherein the weight percentage of each component is: rare earth 1.0%-97.5%, aluminum 2.5%-99.0%, O <0.02%, C <0.03%, P <0.01%, S <0.01%; and the density is 2.70g / cm 3 ‑8.84g / cm 3 , with a melting point of 547°C-1150°C. The use of a porous rare earth aluminum alloy additive helps increase the contact area between the additive and the aluminum alloy melt, improving the additive's dissolution rate, and increasing the additive's buoyancy and viscous resistance in the melt. This overcomes the technical challenge of intermediate alloy additives rapidly sinking to the bottom due to their high density, resulting in a more uniform distribution of rare earth elements in the aluminum alloy melt.

Description

Technical Field

[0001] The present invention relates to the field of rare earth aluminum alloy manufacturing, and in particular to a rare earth aluminum master alloy additive with a porous structure and a preparation method thereof. Background Art

[0002] In recent years, the application of lightweight alloys has garnered increasing attention. Aluminum and its alloys, in particular, are widely used in aerospace, automotive, marine, cable and wire, and building construction due to their low density, excellent electrical and thermal conductivity, corrosion resistance, plasticity, and ease of processing. However, as usage conditions improve, the development of new high-performance aluminum alloys is necessary, and modifying alloy composition is currently one of the key approaches to developing new aluminum alloys. Rare earth elements, as key and effective microalloying elements, are widely used in the preparation of high-performance aluminum and its alloys due to their unique chemical properties.

[0003] Numerous studies have shown that the addition of rare earth elements (REEs), such as silicon, manganese, zinc, magnesium, titanium, boron, and zirconium, to aluminum and its alloys can significantly improve the alloy's mechanical properties, casting properties, corrosion resistance, and electrical properties. These improvements are attributed to the purifying effects of rare earth elements, such as degassing and impurity removal, as well as their excellent refining and modificatory properties. However, due to their high reactivity, susceptibility to oxidation, and severe burnout, and the significant difference in melting points and densities between rare earth elements and aluminum alloys, direct addition is prone to burnout and rapid sinking, making composition control difficult. Therefore, they are typically added to aluminum alloys in the form of master alloys. Currently, the main methods for preparing rare earth aluminum master alloys include melt mixing, doping, molten salt electrolysis, and metallothermic reduction. The melt mixing method involves adding rare earth or mixed rare earth metals in a proportional manner to hot molten aluminum to directly produce the master alloy. Its advantages include simple equipment, ease of operation, and convenient addition of alloying elements. However, its disadvantages are that rare earth elements can easily become over-concentrated in the molten aluminum, leading to peritectic reactions and the formation of inclusions. There are three main molten salt electrolysis methods. The first involves electrolyzing rare earth chlorides or fluorides at a liquid aluminum cathode at relatively low temperatures to produce rare earth aluminum master alloys. The second involves adding rare earth oxides or salts to an industrial aluminum electrolytic cell during aluminum electrolysis, causing rare earth metals to co-precipitate with aluminum, resulting in a rare earth aluminum master alloy. The third involves adding alumina to a graphite electrolytic cell during molten salt electrolysis to produce rare earth aluminum master alloys. The metallothermic reduction method uses aluminum or a calcium-aluminum composite system as a reducing agent, reacting it with rare earth fluorides at high temperatures to produce rare earth aluminum master alloys. These traditional methods all produce solid rare earth aluminum master alloy additives. In practical applications, these additives suffer from high density and limited contact area with the aluminum and aluminum alloy melt. This causes the additives to quickly sink to the bottom of the melt and dissolve slowly, resulting in uneven distribution of rare earth elements and other trace elements, affecting alloy properties. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a porous structure rare earth aluminum master alloy additive and a preparation method thereof. By adopting a porous structure rare earth aluminum alloy additive, it helps to increase the contact area between the additive and the aluminum alloy melt, improve the dissolution rate of the additive, and improve the buoyancy and viscous resistance of the additive in the melt, thereby overcoming the technical problem of the master alloy additive quickly sinking to the bottom due to its own excessive density, and making the distribution of rare earth elements in the aluminum alloy melt more uniform.

[0005] In order to solve the above technical problems, a first aspect of an embodiment of the present invention provides a porous structure rare earth aluminum master alloy additive, comprising: rare earth and aluminum, wherein the rare earth aluminum master alloy additive has a porous structure;

[0006] The weight percentages of the components are as follows: rare earth 1.0%-97.5%, aluminum 2.5%-99.0%, O<0.02%, C<0.03%, P<0.01%, S<0.01%;

[0007] The density of the rare earth aluminum master alloy additive is 2.70g / cm 3 -8.84g / cm 3 , melting point is 547℃-1150℃.

[0008] Furthermore, the rare earth aluminum master alloy additives also include: non-rare earth metals;

[0009] The non-rare earth metal is at least one of silicon, manganese, copper, zinc, titanium, boron and zirconium;

[0010] The weight percentage of the non-rare earth metal is 0%-20.0%, the weight percentage of the rare earth is 1.0%-97.5%; and the weight percentage of the aluminum is 2.5%-99.0%.

[0011] Furthermore, the rare earth element is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, and scandium;

[0012] Preferably, the rare earth element is at least one of lanthanum, cerium, praseodymium, neodymium, scandium, yttrium and erbium.

[0013] Furthermore, the average pore size distribution of the porous structure is 0.1 mm to 5 mm, and the porosity is 5% to 40%.

[0014] Accordingly, a second aspect of an embodiment of the present invention provides a method for preparing a porous rare earth aluminum master alloy additive, which is used to prepare the porous rare earth aluminum master alloy additive, comprising the following steps:

[0015] Selecting and weighing raw materials according to the composition ratio, wherein the raw materials include aluminum ingots, rare earth metals, transition metals and pore-forming agents, or the raw materials include rare earth aluminum master alloys, non-rare earth metals and pore-forming agents;

[0016] Smelting the raw materials to obtain a first rare earth aluminum master alloy;

[0017] Casting the first rare earth aluminum master alloy obtained by smelting, maintaining the temperature at a first preset temperature value during the casting process, to obtain a second rare earth aluminum master alloy;

[0018] The second rare earth aluminum master alloy is distilled and heated at a second preset temperature value under a vacuum environment. The second preset temperature value is lower than the melting point of the rare earth aluminum alloy. The time of the distillation and heating is controlled to control the evaporation amount of the pore-forming agent, and the rare earth aluminum master alloy additive is obtained after the first preset time.

[0019] Furthermore, the composition ratio is: rare earth elements 1.0%-97.5%, aluminum 2.5%-99.0%, non-rare earth metals 0-20.0%, and the amount of pore former is 10.0%-40.0% of the total weight of the above three elements, and the percentages are weight percentages;

[0020] The pore-forming agent includes calcium and / or magnesium; the first preset temperature value ranges from 1000°C to 1400°C;

[0021] The numerical range of the second preset temperature value is 400°C-1000°C;

[0022] The numerical range of the first preset time is 40h-120h.

[0023] Furthermore, the step of smelting the raw materials comprises:

[0024] The aluminum and the pore-forming agent are heated and melted, and after the temperature reaches a third preset temperature value, rare earth metal and non-rare earth metal are added, and the temperature is kept for a second preset time.

[0025] Furthermore, the third preset temperature value has a numerical range of 800° C.-1200° C.;

[0026] The value range of the second preset time is 20 minutes to 40 minutes.

[0027] Furthermore, the step of smelting the raw materials comprises:

[0028] Aluminum, rare earth metal, non-rare earth metal and pore-forming agent are melted in a medium frequency induction melting furnace at a fourth preset temperature value, and are kept warm for a third preset time.

[0029] Furthermore, the fourth preset temperature value has a numerical range of 800° C.-1400° C.;

[0030] The value range of the third preset time is 30 minutes to 60 minutes.

[0031] The above technical solutions of the embodiments of the present invention have the following beneficial technical effects:

[0032] 1. The porous structure helps to increase the specific surface area of ​​the master alloy, thereby improving the buoyancy and viscous resistance of the master alloy, ensuring that the rare earth master alloy does not sink to the bottom, improving the dispersion of rare earth elements in the melt, and improving uniformity;

[0033] 2. The porous structure increases the contact area between the master alloy and the aluminum and its alloy melt, which helps to increase its dissolution rate, ensuring that it can be completely melted before sinking to the bottom during the descent process, and further improving the uniformity of rare earth element dispersion. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of a method for preparing a porous rare earth aluminum master alloy additive provided by an embodiment of the present invention;

[0035] Figure 2a Schematic diagram of the upper surface of the sampling point of the porous rare earth aluminum master alloy additive ingot provided by an embodiment of the present invention;

[0036] Figure 2b It is a schematic diagram of the lower surface of the sampling point of the porous structure rare earth aluminum master alloy additive ingot provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0038] A first aspect of an embodiment of the present invention provides a porous rare earth aluminum master alloy additive, comprising rare earth and aluminum, wherein the rare earth aluminum master alloy additive has a porous structure; wherein the weight percentage of each component is: rare earth 1.0%-97.5%, aluminum 2.5%-99.0%, O <0.02%, C <0.03%, P <0.01%, S <0.01%; the density of the rare earth aluminum master alloy additive is 2.70g / cm 3 -8.84g / cm 3 , melting point is 547℃-1150℃.

[0039] The above technical solution uses a porous structure of rare earth aluminum alloy additives, which helps to increase the contact area between the additives and the aluminum alloy solution, improve the dissolution rate of the additives, and increase the buoyancy and viscous resistance of the additives in the solution. It overcomes the technical problem that the intermediate alloy additives sink to the bottom quickly due to their excessive density, and makes the distribution of rare earth elements in the aluminum alloy solution more uniform.

[0040] Furthermore, the porous structure rare earth aluminum master alloy additive also includes: non-rare earth metal; the non-rare earth metal is at least one of silicon, manganese, copper, zinc, titanium, boron, and zirconium; the weight percentage of the non-rare earth metal is 0%-20.0%, the weight percentage of the rare earth is 1.0%-97.5%; and the weight percentage of the aluminum is 2.5%-99.0%.

[0041] Optionally, the rare earth element is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, and scandium.

[0042] Preferably, the rare earth element is one or more of lanthanum, cerium, praseodymium, neodymium, scandium, yttrium and erbium.

[0043] Specifically, the average pore size distribution of the porous structure is 0.1 mm to 5 mm, and the porosity is 5% to 40%.

[0044] The technical solution of this application can successfully prepare a rare earth aluminum master alloy additive with an average pore size distribution of 0.1mm-5mm and a porosity of 5%-40%. The alloy composition and weight percentage are rare earth: rare earth 1.0%-97.5%, aluminum 2.5%-99.0%, O <0.02%, C <0.03%, P <0.01%, S <0.01%. The alloy density is 2.70g / cm 3 -8.84g / cm 3 , with a melting point of 547°C-1150°C. This approach addresses the technical challenges of uneven composition caused by the rapid sinking and slow dissolution of rare earth master alloys added to aluminum and its alloy melts in the form of blocks or granules, from the perspectives of structure, melting point, and density.

[0045] Accordingly, please refer to Figure 1 A second aspect of the embodiments of the present invention provides a method for preparing a porous rare earth aluminum master alloy additive, which is used to prepare a porous rare earth aluminum master alloy additive, comprising the following steps:

[0046] Step S100 , selecting and weighing raw materials according to the composition ratio, the raw materials including aluminum ingots, rare earth metals, non-rare earth metals and pore formers, or the raw materials including rare earth aluminum master alloys, non-rare earth metals and pore formers.

[0047] In step S100, the composition ratio is: rare earth elements 1.0%-97.5%, aluminum 2.5%-99.0%, non-rare earth metals 0-20.0%; the amount of pore former is 10.0%-40.0% of the total weight of the above three elements, and the pore former includes: calcium and / or magnesium.

[0048] Step S200: smelting the raw materials to obtain a first rare earth aluminum master alloy.

[0049] In step S200 , the numerical range of the first preset temperature value is 1000° C.-1400° C.; the numerical range of the second preset temperature value is 400° C.-1000° C.; and the numerical range of the first preset time is 40h-120h.

[0050] Specifically, in step S200 , the first rare earth aluminum master alloy can be obtained by two methods (melting method or molten salt electrolysis method).

[0051] In one embodiment (melting method), the raw materials are melted in step S200, including:

[0052] In step S210 , aluminum and a pore-forming agent are heated and melted. After the temperature reaches a third preset temperature, rare earth metals and non-rare earth metals are added and kept warm for a second preset time.

[0053] Furthermore, the numerical range of the third preset temperature value is 800° C.-1200° C.; the numerical range of the second preset time is 20 min-40 min.

[0054] Specifically, before step S210, aluminum ingots, rare earth metals, non-rare earth metals, and pore-forming agents such as calcium and magnesium are selected and weighed according to the composition ratio. Calcium / magnesium is evaporated during the subsequent distillation process to create pores in the rare earth aluminum alloy block. The rare earth metals used are prepared by metallothermic reduction or molten salt electrolysis, and the composition ratio is: rare earth elements 1.0%-97.5%, aluminum 2.5%-99.0%, non-rare earth metals 0-20.0%, and the amount of pore-forming agent is 10.0%-40.0% of the total weight of the above three, and the percentages are weight percentages.

[0055] The aluminum ingot and calcium / magnesium are heated and melted. After the temperature reaches a third preset temperature (800° C.-1200° C.), rare earth metals and non-rare earth metals are added and kept warm for 20 min-40 min.

[0056] In another specific embodiment (molten salt electrolysis), in step S100, aluminum, rare earth metal, non-rare earth metal and pore former are smelted according to a preset ratio, including:

[0057] Step S220 , melting aluminum, rare earth metal, non-rare earth metal and pore former in a medium frequency induction melting furnace according to a preset ratio, with the melting temperature being a fourth preset temperature value, and holding the temperature for a third preset time.

[0058] Furthermore, the fourth preset temperature value ranges from 800° C. to 1400° C.; the third preset time value ranges from 30 min to 60 min.

[0059] Specifically, the electrolytic cell uses graphite, a graphite plate as the anode, ① aluminum as the liquid cathode, rare earth fluoride or lithium fluoride as the electrolyte, and rare earth oxides as the raw materials; or ② a tungsten rod as the cathode, rare earth fluoride or lithium fluoride as the electrolyte, and rare earth oxides and aluminum oxide as the raw materials. A molybdenum crucible serves as the rare earth aluminum alloy receiver.

[0060] According to the raw material ratio, rare earth aluminum master alloy prepared by molten salt electrolysis, non-rare earth metals, and pore-forming agents such as calcium and / or magnesium are melted in a medium frequency induction melting furnace at a temperature of 800°C to 1400°C and held at this temperature for 30 to 60 minutes. The raw material composition is 1.0% to 97.5% rare earth elements, 2.5% to 99.0% aluminum, and 0-20.0% non-rare earth metals. The pore-forming agent is used in an amount of 10.0% to 40.0% of the total weight of the above three elements, with the percentages being by weight.

[0061] Step S300 , casting the first rare earth aluminum master alloy obtained by smelting, maintaining the temperature at a first preset temperature value during the casting process, to obtain a second rare earth aluminum master alloy.

[0062] Specifically, the first preset temperature ranges from 1000°C to 1400°C.

[0063] Step S400: Distill and heat the second rare earth aluminum master alloy under a vacuum environment at a second preset temperature value, wherein the second preset temperature value is lower than the melting point of the rare earth aluminum alloy. The distillation and heating time is controlled to control the evaporation amount of the pore-forming agent, and the rare earth aluminum master alloy additive is obtained after the first preset time.

[0064] Specifically, the rare earth aluminum master alloy is placed in a distillation furnace, and the vacuum system adopts a combination of mechanical pump, Roots pump and diffusion pump to a vacuum level of <2.0×10 -2 Pa, turn on the heating system, control the second preset temperature value to be below the melting point of the alloy, control the evaporation amount of calcium / magnesium by controlling the appropriate distillation time, and then control the pore size and porosity of the porous structure rare earth aluminum master alloy, and finally obtain a porous structure rare earth aluminum master alloy additive.

[0065] The following describes in detail the method for preparing a porous rare earth aluminum master alloy additive using several examples:

[0066] Example 1

[0067] Industrial high-purity aluminum ingots, electrolytic lanthanum (La), and high-purity magnesium were used as raw materials, weighed according to the following composition ratio: La: 94.5%, Al: 5.5%, and Mg: 40% of the total weight of La and Al. Al-La-Mg master alloys were prepared using a mixed melt method or a cross-blending method. The alloy was melted at 1000°C, held for 20 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 400°C for 120 hours, with a vacuum level of 0.5×10 - 2 Pa.

[0068] The chemical composition of the porous Al-La master alloy is calculated by mass percentage, including: La: 94.5%, O: 0.0042%, C: 0.0173%, P: 0.0082%, S: 0.0073%, and the rest is Al and unavoidable impurities. The density of the porous Al-La master alloy is 5.97g / cm 3 , melting point is 547℃, average pore diameter is 5mm, and porosity is 40%.

[0069] The porous Al-La master alloy and the Al-La master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Table 1. Rare earth enters the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth elements more evenly distributed in the aluminum alloy.

[0070] Table 1 Test results of La content in aluminum alloy

[0071]

[0072] Example 2

[0073] Industrial high-purity aluminum ingots, electrolytic cerium (Ce), and high-purity calcium were used as raw materials, weighed according to the following composition ratio: Ce: 1.0%, Al: 99.0%, and Ca weight accounting for 30% of the total weight of Ce and Al. Al-Ce-Ca master alloys were prepared using a mixed melt method or a cross-blending method at a melting temperature of 800°C, a holding time of 20 minutes, and then cast. The calcium element was then removed from the alloy by vacuum distillation at a temperature of 550°C for 90 hours, with a vacuum degree of 0.5×10 -2 Pa.

[0074] The chemical composition of the porous Al-Ce master alloy is calculated by mass percentage, including: Ce: 1.0%, O: 0.0052%, C: 0.0153%, P: 0.0062%, S: 0.0034%, and the rest is Al and unavoidable impurities. The density of the porous Al-Ce master alloy is 2.74g / cm 3 , melting point is 660℃, average pore diameter is 3.2mm, and porosity is 28%.

[0075] The porous Al-Ce master alloy and the Al-Ce master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Table 2. Rare earth enters the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth elements more evenly distributed in the aluminum alloy.

[0076] Table 2 Test results of Ce content in aluminum alloy

[0077]

[0078] Example 3:

[0079] Industrial high-purity aluminum ingots, scandium (Sc), and high-purity magnesium were used as raw materials, weighed according to the following composition ratio: Sc: 56.0%, Al: 44.0%, and Mg: 25% of the total weight of Sc and Al. The Al-Sc-Mg master alloy was prepared using a mixed melt method or a cross-blending method. The alloy was melted at 1400°C, held for 30 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 1000°C for 75 hours, with a vacuum level of 1.8×10 - 2 Pa.

[0080] The chemical composition of the porous Al-Sc master alloy, calculated by mass percentage, is as follows: Sc: 56.0%, O: 0.0061%, C: 0.0114%, P: 0.0036%, S: 0.0026%, with the remainder being Al and unavoidable impurities. The porous Al-Sc master alloy has a density of 2.86 g / cm³, a melting point of 1150°C, an average pore diameter of 1.5 mm, and a porosity of 21%.

[0081] The porous Al-Sc master alloy and the Al-Sc master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2aand Figure 2b The test results are shown in Table 2. Rare earth enters the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth elements more evenly distributed in the aluminum alloy.

[0082] Table 3 Test results of Sc content in aluminum alloy

[0083]

[0084] Example 4:

[0085] Industrial high-purity aluminum ingots, metallic lutetium (Lu), and high-purity magnesium were used as raw materials, weighed according to the following composition ratio: Lu: 86.0%, Al: 14.0%, and Mg weight accounting for 10% of the total weight of Sc and Al. Al-Lu-Mg master alloys were prepared using a mixed melt method or a cross-blending method, with a melting temperature of 1200°C, a holding time of 40 minutes, and casting. The magnesium element was then removed from the alloy by vacuum distillation at 1000°C for 40 hours, with a vacuum degree of 1.0×10 - 2 Pa.

[0086] The chemical composition of the porous Al-Lu master alloy is calculated by mass percentage, including: Lu: 86.0%, O: 0.0081%, C: 0.0067%, P: 0.0012%, S: 0.0007%, and the rest is Al and unavoidable impurities. The density of the porous Al-Lu master alloy is 8.84g / cm 3 , melting point is 1110℃, average pore diameter is 0.1mm, and porosity is 5%.

[0087] The porous Al-Lu master alloy and the Al-Lu master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Table 4. Rare earth enters the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth elements more evenly distributed in the aluminum alloy.

[0088] Table 4 Test results of Lu content in aluminum alloy

[0089]

[0090] Example 5:

[0091] Industrial high-purity aluminum ingots, metallic praseodymium (Pr), and high-purity magnesium were used as raw materials, weighed according to the following composition ratio: Pr: 97.5%, Al: 2.5%, and Mg: 20% of the total weight of Pr and Al. The Al-Pr-Mg master alloy was prepared using a mixed melt method or a cross-blending method at a melting temperature of 900°C, a holding time of 30 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 700°C for 60 hours, with a vacuum level of 1.0×10 -2 Pa.

[0092] The chemical composition of the porous Al-Pr master alloy is calculated by mass percentage, including: Pr: 97.5%, O: 0.0063%, C: 0.0076%, P: 0.0032%, S: 0.0023%, and the rest is Al and unavoidable impurities. The density of the porous Al-Pr master alloy is 3.645g / cm 3 , melting point is 795℃, average pore diameter is 1.1mm, and porosity is 18%.

[0093] The porous Al-Pr master alloy and the Al-Pr master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Table 5. Rare earth enters the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth elements more evenly distributed in the aluminum alloy.

[0094] Table 5 Test results of Pr content in aluminum alloy

[0095]

[0096]

[0097] Example 6:

[0098] Industrial high-purity aluminum ingots, neodymium (Nd), high-purity magnesium, and silicon were used as raw materials, weighed according to the following composition ratios: Nd: 30%, Al: 65%, Si: 5.0%, with Mg accounting for 30% of the total weight of Nd, Al, and Si. An Al-Nd-Si-Mg master alloy was prepared using a mixed melt or cross-blending method at a melting temperature of 800°C, a holding time of 30 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 600°C for 90 hours, with a vacuum level of 1.0×10 -2 Pa.

[0099] The chemical composition of the porous Al-Nd-Si master alloy, calculated by mass percentage, includes: Nd: 30.0%, Si: 5.0%, O: 0.0063%, C: 0.0076%, P: 0.0032%, S: 0.0023%, and the remainder is Al and unavoidable impurities. The density of the porous Al-Nd-Si master alloy is 3.971 g / cm 3 , melting point is 720℃, average pore diameter is 3.5mm, and porosity is 31%.

[0100] The porous Al-Nd-Si master alloy and the Al-Nd-Si master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Tables 6 and 7. Rare earth and Si enter the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth and Si elements more evenly distributed in the aluminum alloy.

[0101] Table 6 Test results of Nd content in aluminum alloy

[0102]

[0103] Table 7 Test results of Si content in aluminum alloy

[0104]

[0105]

[0106] Example 7:

[0107] Industrial high-purity aluminum ingots, metallic yttrium (Y), high-purity magnesium, and silicon were used as raw materials, weighed according to the following composition ratios: Y: 32%, Al: 48%, Zn: 20%, with Mg accounting for 30% of the total weight of Y, Al, and Si. The Al-Y-Zn-Mg master alloy was prepared using a mixed melt or cross-blending method at a melting temperature of 1100°C, a holding time of 30 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 900°C for 90 hours, with a vacuum level of 1.0×10 -2 Pa.

[0108] The chemical composition of the porous Al-Y-Zn master alloy, calculated by mass percentage, includes: Y: 32.0%, Zn: 20%, O: 0.0054%, C: 0.0062%, P: 0.0028%, S: 0.0035%, and the remainder is Al and unavoidable impurities. The density of the porous Al-Y-Zn master alloy is 4.154 g / cm3 , melting point is 1095℃, average pore diameter is 3.3mm, and porosity is 30%.

[0109] The porous Al-Y-Zn master alloy and the Al-Y-Zn master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Tables 8 and 9. Rare earth and Zn enter the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth and Zn elements more evenly distributed in the aluminum alloy.

[0110] Table 8 Test results of Y content in aluminum alloy

[0111]

[0112] Table 9 Test results of Zn content in aluminum alloy

[0113]

[0114]

[0115] Example 8:

[0116] Industrial high-purity aluminum ingots, metallic erbium (Er), high-purity magnesium, and copper were used as raw materials, weighed according to the following composition ratio: Er: 55%, Al: 32%, Cu: 13%, with Mg accounting for 30% of the total weight of Er, Al, and Cu. The Al-Er-Cu-Mg master alloy was prepared using a mixed melt or cross-blending method at a melting temperature of 1200°C, a holding time of 40 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 970°C for 90 hours, with a vacuum level of 1.0×10 -2 Pa.

[0117] The chemical composition of the porous Al-Er-Cu master alloy is calculated by mass percentage, including: Er: 55.0%, Cu: 13%, O: 0.0043%, C: 0.0035%, P: 0.0036%, S: 0.0019%, and the rest is Al and unavoidable impurities. The density of the porous Al-Er-Cu master alloy is 7.001g / cm 3 , melting point is 1185℃, average pore diameter is 3.5mm, and porosity is 31%.

[0118] The porous Al-Er-Cu master alloy and the Al-Er-Cu master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Tables 10 and 11. Rare earth and Cu enter the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth and Cu elements more evenly distributed in the aluminum alloy.

[0119] Table 10 Test results of Er content in aluminum alloy

[0120]

[0121] Table 11 Test results of Cu content in aluminum alloy

[0122]

[0123] Example 9:

[0124] Industrial high-purity aluminum ingots, yttrium (Y), high-purity magnesium, and titanium were used as raw materials, weighed according to the following composition ratio: Y: 1%, Al: 98%, Ti: 1%, with Mg accounting for 30% of the total weight of Y, Al, and Ti. An Al-Y-Ti-Mg master alloy was prepared using a mixed melt or cross-blending method at a melting temperature of 900°C, a holding time of 40 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 700°C for 90 hours, with a vacuum level of 1.0×10 -2 Pa.

[0125] The chemical composition of the porous Al-Y-Ti master alloy is calculated by mass percentage, including: Y: 1.0%, Ti: 1%, O: 0.0063%, C: 0.0042%, P: 0.0018%, S: 0.0033%, and the rest is Al and unavoidable impurities. The density of the porous Al-Y-Ti master alloy is 2.736g / cm 3 , melting point is 1185℃, average pore diameter is 3.5mm, and porosity is 31%.

[0126] The porous Al-Y-Ti master alloy and the Al-Y-Ti master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2bThe test results are shown in Tables 12 and 13. Rare earth and Ti enter the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth and Ti elements more evenly distributed in the aluminum alloy.

[0127] Table 12 Test results of Y content in aluminum alloy

[0128]

[0129] Table 13 Test results of Ti content in aluminum alloy

[0130]

[0131] Example 10:

[0132] Industrial high-purity aluminum ingots, metallic cerium (Ce), high-purity magnesium, and boron were used as raw materials, weighed according to the following composition ratio: Ce: 95%, Al: 4%, and B: 1%. The weight of Mg was 30% of the total weight of Ce, Al, and B. The Al-Ce-B-Mg master alloy was prepared using a mixed melt method or a cross-blending method. The alloy was melted at 1300°C, held for 40 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 1000°C for 90 hours, with a vacuum of 1.0×10 -2 Pa.

[0133] The chemical composition of the porous Al-Ce-B master alloy is calculated by mass percentage as follows: Ce: 95%, B: 1%, O: 0.0046%, C: 0.0047%, P: 0.0023%, S: 0.0016%, and the remainder is Al and unavoidable impurities. The density of the porous Al-Ce-B master alloy is 6.564g / cm 3 , melting point is 1135℃, average pore diameter is 3.2mm, and porosity is 28%.

[0134] The porous Al-Ce-B master alloy and the Al-Ce-B master alloy prepared by the mixed melting method or the cross-blending method are respectively added to the aluminum alloy through the medium frequency melting furnace and finally cast into an ingot. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Tables 14 and 15. The rare earth and B enter the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth and B elements more evenly distributed in the aluminum alloy.

[0135] Table 14 Test results of Ce content in aluminum alloy

[0136]

[0137]

[0138] Table 15 Test results of B content in aluminum alloy

[0139]

[0140] Example 11:

[0141] Industrial high-purity aluminum ingots, metallic lanthanum (La), high-purity magnesium, and manganese were used as raw materials, weighed according to the following composition ratios: La: 94.5%, Al: 2.5%, and Mn: 2.5%, with the weight of Mg accounting for 30% of the total weight of La, Al, and Mn. An Al-La-Mn-Mg master alloy was prepared using a mixed melt or cross-blending method at a melting temperature of 800°C, a holding time of 30 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at a temperature of 550°C for 90 hours, with a vacuum level of 1.0×10 -2 Pa.

[0142] The chemical composition of the porous Al-La-Mn master alloy, calculated by mass percentage, includes: La: 94.5%, Mn: 3%, O: 0.0042%, C: 0.0049%, P: 0.0032%, S: 0.0024%, and the remainder is Al and unavoidable impurities. The density of the porous Al-La-Mn master alloy is 6.112 g / cm 3 , melting point is 645℃, average pore diameter is 3.4mm, and porosity is 30%.

[0143] The porous Al-La-Mn master alloy and the Al-La-Mn master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Tables 16 and 17. Rare earth and Mn enter the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth and Mn elements more evenly distributed in the aluminum alloy.

[0144] Table 16 Test results of La content in aluminum alloy

[0145]

[0146]

[0147] Table 17 Test results of Mn content in aluminum alloy

[0148]

[0149] Example 12:

[0150] Industrial high-purity aluminum ingots, metallic lanthanum (La), high-purity magnesium, and zirconium were used as raw materials, weighed according to the following composition ratio: La: 94.5%, Al: 5%, Zr: 0.5%, with Mg accounting for 30% of the total weight of La, Al, and Zr. The Al-La-Zr-Mg master alloy was prepared using a mixed melt method or a cross-blending method at a melting temperature of 800°C, a holding time of 30 minutes, and then cast. The magnesium element was then removed from the alloy by vacuum distillation at 450°C for 90 hours, with a vacuum level of 1.0×10 -2 Pa.

[0151] The chemical composition of the porous Al-La-Zr master alloy, calculated by mass percentage, includes: La: 94.5%, Zr: 0.5%, O: 0.0038%, C: 0.0022%, P: 0.0036%, S: 0.0017%, and the remainder is Al and unavoidable impurities. The density of the porous Al-La-Zr master alloy is 5.989 g / cm 3 , melting point is 550℃, average pore diameter is 3.5mm, and porosity is 31%.

[0152] The porous Al-La-Zr master alloy and the Al-La-Zr master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Tables 18 and 19. Rare earth and Zr enter the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth and Zr elements more evenly distributed in the aluminum alloy.

[0153] Table 18 Test results of La content in aluminum alloy

[0154]

[0155]

[0156] Table 19 Test results of Zr content in aluminum alloy

[0157]

[0158] Example 13:

[0159] Yttrium aluminum alloy and high-purity magnesium prepared by molten salt electrolysis were used as raw materials, and the composition ratio was weighed according to the following: Y accounts for 82% of the yttrium aluminum alloy, Al accounts for 18%, and Mg accounts for 20% of the weight of the yttrium aluminum alloy. The Al-Y-Mg master alloy was prepared by a mixed melting method or a cross-blending method, with a melting temperature of 1200°C, a holding time of 30 minutes, and a casting process. The magnesium element was then removed from the alloy by vacuum distillation at 1000°C for 60 hours, with a vacuum degree of 1.0×10 -2 Pa.

[0160] The chemical composition of the porous Al-Y master alloy is calculated by mass percentage, including: Y: 82.0%, O: 0.0036%, C: 0.0121%, P: 0.0011%, S: 0.0008%, and the rest is Al and unavoidable impurities. The density of the porous Al-Y master alloy is 4.151g / cm 3 , melting point is 1100℃, average pore diameter is 1.1mm, and porosity is 18%.

[0161] The porous Al-Y master alloy and the Al-Y master alloy prepared by the mixed melting method or the cross-blending method are added to the aluminum alloy through the medium frequency melting furnace and finally cast into ingots. Three points are taken at equal distances on the upper and lower surfaces of the ingot. The positions of the sampling points are as follows: Figure 2a and Figure 2b The test results are shown in Table 12. Rare earth enters the aluminum melt in the form of a porous rare earth aluminum master alloy, which can make the rare earth elements more evenly distributed in the aluminum alloy.

[0162] Table 20 Test results of Y content in aluminum alloy

[0163]

[0164] The embodiments of the present invention are intended to protect a porous rare earth aluminum master alloy additive and a preparation method thereof, wherein the porous rare earth aluminum master alloy additive comprises rare earth and aluminum, and the rare earth aluminum master alloy additive has a porous structure; wherein the weight percentages of the components are: rare earth 1.0%-97.5%, aluminum 2.5%-99.0%, O < 0.02%, C < 0.03%, P < 0.01%, S < 0.01%; the density of the rare earth aluminum master alloy additive is 2.70 g / cm 3 -8.84g / cm 3 , with a melting point of 547°C-1150°C. The above technical solution has the following effects:

[0165] 1. The porous structure helps to increase the specific surface area of ​​the master alloy, thereby improving the buoyancy and viscous resistance of the master alloy, ensuring that the rare earth master alloy does not sink to the bottom, improving the dispersion of rare earth elements in the melt, and improving uniformity;

[0166] 2. The porous structure increases the contact area between the master alloy and the aluminum and its alloy melt, which helps to increase its dissolution rate, ensuring that it can be completely melted before sinking to the bottom during the descent process, and further improving the uniformity of rare earth element dispersion.

[0167] It should be understood that the above-described specific embodiments of the present invention are merely illustrative or illustrative of the principles of the present invention and do not constitute limitations of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the scope of protection of the present invention. In addition, the appended claims are intended to cover all variations and modifications that fall within the scope and metes and bounds of the appended claims, or equivalents thereof.

Claims

1. A method for preparing a porous rare earth aluminum master alloy additive, characterized in that: The rare earth aluminum master alloy additive has a porous structure with an average pore size distribution of 0.1 mm to 5 mm and a porosity of 5% to 40%. The weight percentage of each component is as follows: rare earth 1.0% to 97.5%, O < 0.02%, C < 0.03%, P < 0.01%, S < 0.01%, and the rest is aluminum and unavoidable impurities. The density of the rare earth aluminum master alloy additive is 2.70 g / cm 3 -8.84g / cm 3 , melting point is 547 ℃-1150 ℃; The preparation method comprises the following steps: Selecting and weighing raw materials according to the composition ratio, wherein the raw materials include aluminum ingots, rare earth metals and pore-forming agents; Smelting the raw materials to obtain a first rare earth aluminum master alloy; Casting the first rare earth aluminum master alloy obtained by smelting, maintaining the temperature at a first preset temperature value during the casting process, to obtain a second rare earth aluminum master alloy; The second rare earth aluminum master alloy is distilled and heated at a second preset temperature value under a vacuum environment. The second preset temperature value is lower than the melting point of the rare earth aluminum alloy. The time of the distillation and heating is controlled to control the evaporation amount of the pore-forming agent. The rare earth aluminum master alloy additive is obtained after the first preset time.

2. The method for preparing a porous rare earth aluminum master alloy additive according to claim 1, characterized in that: The rare earth element is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, and scandium.

3. The method for preparing a porous rare earth aluminum master alloy additive according to claim 2, characterized in that: The rare earth element is at least one of lanthanum, cerium, praseodymium, neodymium, scandium, yttrium and erbium.

4. The method for preparing a porous rare earth aluminum master alloy additive according to any one of claims 1 to 3, characterized in that: The composition ratio is: rare earth elements 1.0%-97.5%, aluminum 2.5%-99.0%, the amount of pore-forming agent is 10.0%-40.0% of the total weight of the above two, and the percentage is weight percentage; The pore-forming agent includes: calcium and / or magnesium; The numerical range of the first preset temperature value is 1000°C-1400°C; The numerical range of the second preset temperature value is 400°C-1000°C; The numerical range of the first preset time is 40 h-120 h.

5. The method for preparing a porous rare earth aluminum master alloy additive according to any one of claims 1 to 3, characterized in that: The step of smelting the raw materials comprises: The aluminum ingot and the pore-forming agent are heated and melted in a medium frequency induction melting furnace. After the temperature is raised to a third preset temperature value, rare earth metals are added and the temperature is kept for a second preset time.

6. The method for preparing a porous rare earth aluminum master alloy additive according to claim 5, characterized in that: The third preset temperature value has a numerical range of 800°C-1200°C; The value range of the second preset time is 20 minutes to 40 minutes.

7. The method for preparing a porous rare earth aluminum master alloy additive according to any one of claims 1 to 3, characterized in that: The step of smelting the raw materials comprises: Aluminum, rare earth metals and pore-forming agents are melted in a medium frequency induction melting furnace at a fourth preset temperature value, and are kept warm for a third preset time.

8. The method for preparing a porous rare earth aluminum master alloy additive according to claim 7, characterized in that: The fourth preset temperature value has a numerical range of 800°C-1200°C; The value range of the third preset time is 30 minutes to 60 minutes.

9. The method for preparing a porous rare earth aluminum master alloy additive according to claim 1, characterized in that: The raw materials of the porous structure rare earth aluminum master alloy additive also include: non-rare earth metals; The non-rare earth metal is at least one of silicon, manganese, copper, zinc, titanium, boron and zirconium; The weight percentages of the components are as follows: the weight percentage of the non-rare earth metal is 0.1%-20.0%, the weight percentage of the rare earth is 1.0%-97.5%; and the rest are aluminum and unavoidable impurities.

10. The method for preparing a porous rare earth aluminum master alloy additive according to claim 9, characterized in that: The rare earth element is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, and scandium.

11. The method for preparing a porous rare earth aluminum master alloy additive according to claim 10, characterized in that: The rare earth element is at least one of lanthanum, cerium, praseodymium, neodymium, scandium, yttrium and erbium.

12. The method for preparing a porous rare earth aluminum master alloy additive according to any one of claims 9 to 11, characterized in that: The composition ratio is: rare earth elements 1.0%-97.5%, aluminum 2.5%-99.0%, non-rare earth metals 0.1-20.0%, the amount of pore-forming agent is 10.0%-40.0% of the total weight of the above three elements, and the percentages are weight percentages; The pore-forming agent includes: calcium and / or magnesium; The numerical range of the first preset temperature value is 1000°C-1400°C; The numerical range of the second preset temperature value is 400°C-1000°C; The numerical range of the first preset time is 40 hours to 120 hours.

13. The method for preparing a porous rare earth aluminum master alloy additive according to any one of claims 9 to 11, characterized in that: The step of smelting the raw materials comprises: The aluminum ingot and the pore-forming agent are heated and melted in a medium frequency induction melting furnace. After the temperature is raised to a third preset temperature value, rare earth metals and non-rare earth metals are added and kept warm for a second preset time.

14. The method for preparing a porous rare earth aluminum master alloy additive according to claim 13, characterized in that: The third preset temperature value has a numerical range of 800°C-1200°C; The value range of the second preset time is 20 minutes to 40 minutes.

15. The method for preparing a porous rare earth aluminum master alloy additive according to any one of claims 9 to 11, characterized in that: The step of smelting the raw materials comprises: Aluminum, rare earth metal, non-rare earth metal and pore-forming agent are melted in a medium frequency induction melting furnace at a fourth preset temperature value, and are kept warm for a third preset time.

16. The method for preparing a porous rare earth aluminum master alloy additive according to claim 15, characterized in that: The fourth preset temperature value has a numerical range of 800°C-1200°C; The value range of the third preset time is 30 minutes to 60 minutes.

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