Preparation method for synergistic optimization of grain refinement and ignition performance of rare earth ignition alloy

Abstract

The application relates to a grain refinement and ignition performance synergic optimization preparation method of a rare earth ignition alloy, and belongs to the technical field of rare earth ignition alloy manufacturing. According to percentages, the preparation raw material of the blank includes 35-45% of lanthanum, 15-30% of cerium, 5-15% of tin, 5-10% of zinc, 5-10% of praseodymium, 1-5% of neodymium and 15-25% of iron. The synergic action of the nanoscale active metal additive and the blank enables the rare earth ignition alloy to generate continuous sparks under slight friction or impact, and improves the ignition performance of the traditional rare earth ignition alloy.

Description

Technical Field

[0001] This invention belongs to the field of rare earth ignition alloy manufacturing technology, specifically relating to a method for synergistically optimizing the grain refinement and ignition performance of rare earth ignition alloys. Background Technology

[0002] Ignition alloys, also known as ignition alloys or flint alloys, are powdered alloys that spontaneously combust upon contact with air. They mainly include rare earth alloys, zirconium alloys, and metal powders such as iron, cobalt, nickel, vanadium, titanium, and manganese. These metal powders are collectively referred to as ignition metals, which are divided into non-rare earth and rare earth types.

[0003] Traditional rare earth ignition alloys have relatively coarse grains, which are prone to forming inclusions, pores, or uneven grain size. This results in large fluctuations in hardness and tensile strength. Some products are prone to breakage under repeated impacts or friction, easily producing "fragments" and failing to ignite continuously. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing rare earth ignition alloys that synergistically optimizes grain refinement and ignition performance in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] This invention provides a method for synergistically optimizing the grain refinement and ignition performance of rare earth ignition alloys. The method for preparing rare earth ignition alloys includes the following steps:

[0007] (1) Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850-1050℃ and held for 5-6 hours to obtain molten metal;

[0008] (2) Grain refinement: The molten metal is poured into a tundish preheated to 900°C. The molten metal flows out at a speed of 1-5 m / s in a stable and continuous flow form through the nozzle at the bottom of the tundish. Below the nozzle, a pre-set atomizing nozzle sprays atomizing medium at 300-600 m / s to interact with the molten metal and shear the molten metal into atomized droplets. The atomized droplets are injected into the condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0009] (3) Adding active metals for synergistic optimization: Add the active metal additives and solid powder particles to the stirrer at 25r / min for 5-10min, then apply ultrasonic vibration at a frequency of 20-40kHz for 10-15min to obtain the preform.

[0010] (4) Spark plasma sintering: The preform is placed in the sintering chamber and spark plasma sintering is carried out in a nitrogen atmosphere. After cooling, a rare earth ignition alloy is obtained.

[0011] As a further optimization of the present invention, the raw materials for preparing the billet, by percentage, include 35-45% lanthanum, 15-30% cerium, 5-15% tin, 5-10% zinc, 5-10% praseodymium, 1-5% neodymium, and 15-25% iron.

[0012] As a further optimization of the present invention, the billet preparation process is as follows: weigh each component raw material according to the mass percentage, put them into the melting furnace together, and then melt them at high temperature in the absence of oxygen; after each component raw material is melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in the absence of oxygen to obtain the billet.

[0013] As a further optimization of the present invention, the atomizing medium in step (2) is nitrogen.

[0014] As a further optimization of the present invention, the preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder and aluminum powder are mixed to obtain the active metal additive; wherein, the preparation process of the iron powder is as follows: hydrogen is used to reduce rolled steel phosphorus to obtain sponge iron, which is then crushed and sieved to obtain iron powder; the preparation process of the titanium powder is as follows: magnesium is used to reduce titanium chloride to obtain sponge titanium, which is then crushed and sieved to obtain titanium powder; the particle size of magnesium powder, iron powder, titanium powder and aluminum powder is 10-15 nm.

[0015] As a further optimization of the present invention, the mass ratio of magnesium powder, iron powder, titanium powder and aluminum powder is 1:0.5:0.3:0.8.

[0016] As a further optimization of the present invention, the mass ratio of active metal additive to solid powder particles is 0.2:1.

[0017] As a further optimization of the present invention, in step (1), the temperature is increased at a rate of 7℃ / min; in step (4), the discharge plasma sintering is carried out at a pressure of 50MPa-60MPa, the temperature is increased to 600℃-700℃ at a rate of 200℃ / min, and held for 3min-6min; in step (4), the temperature is decreased at a rate of 8℃ / min.

[0018] The beneficial effects of this invention are as follows: This invention uses nano-level active metal additives in synergy with the billet, enabling rare earth ignition alloys to generate continuous sparks under slight friction or impact, thus increasing the ignition performance of traditional rare earth ignition alloys. Furthermore, it employs an atomizing medium that interacts with the molten metal, shearing the molten metal into atomized droplets. These atomized droplets solidify in a condensation tower to form fine spherical powders. After spark plasma sintering, the grains of these fine spherical powders do not grow large in a very short time, resulting in a rare earth ignition alloy with high-density, fine grains, uniform internal particle size, small fluctuations in hardness and tensile strength, and resistance to breakage under repeated impact or friction, allowing for continuous ignition. Detailed Implementation

[0019] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products.

[0021] Example 1

[0022] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 35% lanthanum, 15% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, under the condition of oxygen isolation, high-temperature melting is carried out. After each component raw material melts, it is mixed evenly by electromagnetic stirring, removed from the furnace, and cooled and cast into ingots under the condition of oxygen isolation to obtain the billet.

[0023] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0024] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0025] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0026] Synergistic optimization with the addition of active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 5 min. Then, ultrasonic vibration at a frequency of 20 kHz was applied for 10 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0027] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held for 3 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0028] Example 2

[0029] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 40% lanthanum, 20% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 15% iron into a melting furnace. Then, melt at high temperature in an oxygen-isolated state. After the raw materials are melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

[0030] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0031] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 900℃ at a rate of 7℃ / min and held for 5.5h to obtain molten metal;

[0032] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 3 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 450 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0033] Synergistic optimization with added active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 7 min. Then, ultrasonic vibration at a frequency of 30 kHz was applied for 12 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0034] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 650°C at a pressure of 55 MPa at a rate of 200°C / min, held for 4 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0035] Example 3

[0036] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 40% lanthanum, 17% cerium, 5% tin, 5% zinc, 9% praseodymium, 4% neodymium and 20% iron into a melting furnace. Then, melt at high temperature in an oxygen-isolated state. After the raw materials are melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

[0037] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0038] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 1050℃ at a rate of 7℃ / min and held for 6 hours to obtain molten metal;

[0039] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 5 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 600 m / s to interact with the molten metal, shearing the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0040] Synergistic optimization with added active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 10 min. Then, ultrasonic vibration at a frequency of 40 kHz was applied for 15 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0041] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 700°C at a pressure of 60 MPa at a rate of 200°C / min, held for 6 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0042] Comparative Example 1

[0043] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 50% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, melt at high temperature in an oxygen-isolated state. After the raw materials are melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

[0044] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0045] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0046] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0047] Synergistic optimization with the addition of active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 5 min. Then, ultrasonic vibration at a frequency of 20 kHz was applied for 10 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0048] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held for 3 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0049] Comparative Example 2

[0050] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 50% lanthanum, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, melt at high temperature in an oxygen-isolated state. After the raw materials are melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

[0051] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0052] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0053] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0054] Synergistic optimization with the addition of active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 5 min. Then, ultrasonic vibration at a frequency of 20 kHz was applied for 10 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0055] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held for 3 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0056] Comparative Example 3

[0057] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 35% lanthanum, 15% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, under the condition of oxygen isolation, high-temperature melting is carried out. After each component raw material melts, it is mixed evenly by electromagnetic stirring, removed from the furnace, and cooled and cast into ingots under the condition of oxygen isolation to obtain the billet.

[0058] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0059] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0060] Spark plasma sintering: Solid powder particles are placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held at that temperature for 3 min, and then cooled at a rate of 8°C / min to obtain rare earth ignition alloy.

[0061] Comparative Example 4

[0062] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 35% lanthanum, 15% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, under the condition of oxygen isolation, high-temperature melting is carried out. After each component raw material melts, it is mixed evenly by electromagnetic stirring, removed from the furnace, and cooled and cast into ingots under the condition of oxygen isolation to obtain the billet.

[0063] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; the particle size of the magnesium powder, iron powder, titanium powder and aluminum powder is 10-15nm.

[0064] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0065] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0066] Synergistic optimization with the addition of active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 5 min. Then, ultrasonic vibration at a frequency of 20 kHz was applied for 10 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0067] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held for 3 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0068] Performance testing

[0069] ①The Vickers hardness of the rare earth ignition alloys prepared by the methods of Examples 1-3 and Comparative Examples 1-4 was tested according to the test methods in GB / T 4340.1-2009 "Metallic Materials - Vickers Hardness Test".

[0070] ② The density of the rare earth ignition alloys prepared by the methods in Examples 1-3 and Comparative Examples 1-4 was tested according to the test methods in GB / T 1423-1996 "Test Methods for Density of Precious Metals and Their Alloys";

[0071] ③ The rare earth ignition alloys prepared by the methods in Examples 1-3 and Comparative Examples 1-4 were subjected to thermal fatigue testing according to the test methods in GB / T 13303-2021 "Determination of Oxidation Resistance of Steel". The samples were kept at 300℃ for 2 hours, and the presence of an oxide layer was observed. At the same time, their coefficient of thermal expansion was measured. The test results are shown in Table 1.

[0072] Table 1

[0073]

[0074] As can be seen from Table 1, by comparing the test data obtained from Examples 1-3 of the experimental group, it can be seen that Example 1 has better overall performance. By comparing Example 1, which has the best performance among the examples, with Comparative Examples 1-4, it can be seen that Example 1 is also better than any of the Comparative Examples 1-4.

[0075] Comparing Example 1 with Comparative Example 1, it can be found that Comparative Example 1 did not use lanthanum but increased the amount of cerium added. The lack of lanthanum resulted in a relative decrease in Vickers hardness and density compared to Example 1, and a decrease in thermal fatigue resistance. Comparing Example 1 with Comparative Example 2, it can be found that Comparative Example 2 did not use cerium but increased the amount of lanthanum added. This resulted in similar test values ​​between Comparative Example 2 and Comparative Example 1, indicating that lanthanum and cerium have a synergistic effect. A suitable component ratio can improve the performance of rare earth ignition alloys.

[0076] Comparing Example 1 with Comparative Example 3, it can be found that Comparative Example 3 did not add active metals and solid powder particles for synergistic optimization. The test results confirm that the rare earth ignition alloy with added active metals has superior performance.

[0077] Comparing Example 1 with Comparative Example 4, it can be found that Comparative Example 4 added ordinary iron powder and titanium powder, and the test results are slightly different from those of Example 1.

[0078] ④ The tensile strength and elongation of the rare earth ignition alloys prepared by the methods in Example 1 and Comparative Examples 1-4 were tested according to the test methods in GB / T 228.1-2010 "Metallic materials, tensile testing - Part 1: Test method at room temperature". The test results are shown in Table 2.

[0079] Table 2

[0080]

[0081] As can be seen from Table 2, Example 1 has better physical properties than Comparative Examples 1-4, with better tensile strength and elongation.

[0082] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for synergistically optimizing grain refinement and ignition performance of rare earth ignition alloys, characterized in that, The preparation method of rare earth ignition alloys includes the following steps: (1) Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850-1050℃ and held for 5-6 hours to obtain molten metal; (2) Grain refinement: The molten metal is poured into a tundish preheated to 900°C. The molten metal flows out at a speed of 1-5 m / s in a stable and continuous flow form through the nozzle at the bottom of the tundish. Below the nozzle, a pre-set atomizing nozzle sprays atomizing medium at 300-600 m / s to interact with the molten metal and shear the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles. (3) The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder and aluminum powder are mixed to obtain the active metal additive; wherein, the preparation process of the iron powder is as follows: hydrogen is used to reduce the phosphorus in rolled steel to obtain sponge iron, and then the iron powder is obtained by crushing and sieving; the preparation process of the titanium powder is as follows: magnesium is used to reduce titanium chloride to obtain sponge titanium, and then the titanium powder is obtained by crushing and sieving; the particle size of the magnesium powder, iron powder, titanium powder and aluminum powder is 10-15 nm; (4) Adding active metals for synergistic optimization: Add the active metal additives and solid powder particles to the stirrer at 25r / min for 5-10min, then apply ultrasonic vibration at a frequency of 20-40kHz for 10-15min to obtain the preform. (5) Spark plasma sintering: The preform is placed in the sintering chamber and spark plasma sintering is carried out in a nitrogen atmosphere. After cooling, a rare earth ignition alloy is obtained.

2. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 1, characterized in that, The raw materials for preparing the billet, by percentage, include 35-45% lanthanum, 15-30% cerium, 5-15% tin, 5-10% zinc, 5-10% praseodymium, 1-5% neodymium, and 15-25% iron.

3. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 2, characterized in that, The billet preparation process is as follows: weigh each component raw material according to the mass percentage, put them into the melting furnace together, and then melt them at high temperature in an oxygen-isolated state; after each component raw material melts, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

4. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 1, characterized in that, In step (2), the atomizing medium is nitrogen.

5. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 1, characterized in that, The mass ratio of magnesium powder, iron powder, titanium powder and aluminum powder is 1:0.5:0.3:0.

8.

6. The method for synergistically optimizing grain refinement and ignition performance of rare earth ignition alloys according to claim 5, characterized in that, The mass ratio of the active metal additive to the solid powder particles is 0.2:

1.

7. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 1, characterized in that, In step (1), the temperature is increased at a rate of 7℃ / min; in step (4), the discharge plasma sintering is carried out at a pressure of 50MPa-60MPa, the temperature is increased to 600℃-700℃ at a rate of 200℃ / min, and held for 3min-6min; in step (4), the temperature is decreased at a rate of 8℃ / min.

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