A method for preparing a low-temperature in-situ synthesized nanoparticle reinforced aluminum matrix composite

Abstract

The application discloses a kind of low-temperature in-situ synthesis nanoparticle reinforced aluminum matrix composite preparation method, with the following characteristics: (1) the calculation method of the application is used, the initial melting amount of alloy and the size of crucible are reasonably selected, and the depth of molten salt layer in the reaction process is controlled to be not more than 3 cm;(2) Al-Si eutectic alloy is used as the base melt, mixed salt is added at 600 DEG C, and the melt temperature during the whole reaction process is not more than 650 DEG C;(3) vacuum purification treatment, heating and adding alloy elements are carried out in sequence after the reaction is completed.The application uses reasonable crucible diameter and very low reaction temperature, effectively reduces the reaction speed and inhibits the growth speed of reaction products, solves the problem of large particle size distribution range and multiple by-products of traditional in-situ synthesis method. By strictly controlling the depth of metal melt and molten salt, the alloy-molten salt reaction interface is increased, the reaction product is more easily dispersed, the residual molten salt in the melt is significantly reduced, and the difficulty of melt purification is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aluminum matrix composite material preparation, and particularly relates to a method for preparing a low-temperature in-situ synthesized nanoparticle reinforced aluminum matrix composite material. BACKGROUND

[0002] The nanoparticle reinforced aluminum matrix composite material not only exhibits excellent mechanical properties, but also has high wear resistance, good thermal conductivity, low thermal expansion coefficient, strong designability and the like, and has a broad application prospect in the field of advanced equipment manufacturing. The in-situ synthesis method can directly generate thermodynamically stable reinforcing particles in the melt. The reinforcing particles nucleate and grow in the melt, and have natural wettability with the melt. The interface between the reinforcing particles and the matrix is pure and has high bonding strength. Therefore, the in-situ synthesized particle reinforced aluminum matrix composite material is considered to be the most promising composite material preparation technology. The fluorine salt method has the advantages of simple process and low cost, and is the most promising method for in-situ synthesis of nanoparticle reinforced aluminum matrix composite material.

[0003] However, the fluorine salt method for in-situ synthesis of nanoparticle reinforced aluminum matrix composite material has not been widely used in engineering applications, mainly because the bottleneck technical problems have not been solved:

[0004] First, the reinforcing particle size distribution range is wide, ranging from several hundred nanometers to several microns, and the existence of large-size particles limits the strengthening effect of the nanoparticles; second, the uniformity of the dispersion of the nanoparticles in the matrix is poor, and the agglomerated nanoparticles actually reduce the mechanical properties of the matrix material; third, the residual molten salt in the melt is difficult to completely remove, and the purity of the melt is poor, which greatly reduces the effect of particle reinforcement (Hudongfu. Preparation of high-purity in-situ TiB2 reinforced aluminum matrix composite material [D]. Dalian: Dalian University of Technology, 2014.).

[0005] In order to obtain reinforcing particles with high size concentration and good dispersion, technical personnel at home and abroad generally use a lower reaction temperature, and at the same time implement strong stirring (including electromagnetic stirring and mechanical stirring).

[0006] Chinese patent 202011306962.1 discloses a method for preparing in-situ nanoparticle reinforced aluminum matrix composites at low temperature. The melt temperature is controlled at 660-670℃, a high-speed mechanical stirring is applied on the surface of the melt to form a vortex, and mixed salt is added to the vortex on the surface of the melt and reacted for 15 minutes. The reaction between mixed salt and Al is an exothermic reaction, which causes the melt temperature to rise by about 90℃. This technology does not consider the impact of the rise of melt temperature on the reaction process. In addition, the high-speed rotating surface vortex will wrap the mixed salt and air into the interior of the melt, forming a large amount of residual emulsified salt and a large amount of oxides in the interior of the melt, resulting in an increase in the viscosity of the melt and bringing difficulties to the purification treatment of the melt. This method does not involve purification technology for residual emulsified salt and oxide inclusions. The research of Liu Zhengcai et al. (Liu Zhengcai, et al. Research Status of TiB2 Particle Reinforced Aluminum Matrix Composites by Mixed Salt Method [J]. Hot Working Technology, 2021, 12(50) pp: 17-21) shows that mechanical stirring can effectively promote melt flow and promote melt homogenization. However, low-speed stirring cannot effectively break clusters, while high-speed stirring can increase hydrogen absorption and oxidation, and can introduce surface impurities, thereby reducing the mechanical properties of the composite material.

[0007] Wang Hao-wei team proposed a system and method for preparing in-situ self-grown aluminum matrix composites using pulse magnetic field. Mixed salt is added at 700-760℃ while vacuum is extracted (a method for controlling in-situ self-grown aluminum matrix composites with electromagnetic stirring of melt, Chinese patent 202011571152.9; a system for controlling in-situ self-grown aluminum matrix composites with electromagnetic stirring of melt, Chinese patent 202011571153.3; a method for in-situ self-grown aluminum matrix composites with permanent magnetic stirring, Chinese patent 202011571141.0). This technology does not involve research on the impact of reaction exothermicity and melt temperature rise on the reaction process, nor does it involve research on residual melt salt purification technology.

[0008] To avoid the problems of melt temperature rise and stirring caused by fluorine method reaction process, Chinese patent 202111585762.9 proposes a method for preparing TiB2 in-situ reinforced aluminum matrix composites. This method uses boron alloy and aluminum-titanium alloy or pure titanium as raw materials, reacts at 800-850℃, and uses argon refining to remove gas. This technology has a high reaction temperature, does not involve mixed salt reaction, and does not involve residual melt salt purification technology.

[0009] Chinese patent 200510029902.9 discloses a method for preparing in-situ particle reinforced high-temperature-resistant aluminum matrix composites. The reaction temperature range disclosed in the method is 680-800℃, after the reaction is completed, alloying elements are added, and vacuum is extracted and left. The reaction temperature of this method is relatively high, and the influence of the increase of the reaction temperature on the reaction process is not involved; after the reaction is completed, the residual salt in the melt is not treated in time, and the addition of alloying elements will cause the further increase of the viscosity of the melt, leading to the more difficult purification treatment of the melt.

[0010] Wang et al. used mechanical stirring during the reaction process, reacted at 850℃, and obtained the tensile strength of TiB2(2.2vol%) / A356 composite material of 375.3MPa, the yield strength of 304.7MPa, and the elongation of 4.88%(Wang, Mechanical properties of in-situ TiB2 / A356 composites[J]. Materials Science & Engineering A, 590(2014)246-254). He Yongsheng et al. used C2Cl6 refining, added mixed salt at 720℃, fully stirred, and sand casting obtained 5wt% / ZL114A composite material performance tensile strength 300MP, elongation 2.5%(He Yongsheng, et al. Microstructure and mechanical properties of in-situ TiB2 particle reinforced TiB2 / Al-7%Si-05%Mg composites[J]. Foundry, 2000(07):396-397.). The reaction temperature of the above researches is relatively high, and the influence of the heat release of the reaction and the increase of the melt temperature on the reaction process is not involved.

[0011] The inventors' team found through experimental research that when the melting amount is several hundred kilograms to several tons, the melt temperature rises by about 80-100℃ during the reaction process. The large increase of the melt temperature leads to the increase of the reaction speed, while the convection or diffusion speed (constant mechanical stirring or equal-power acoustic-magnetic coupling field) remains unchanged, which inevitably causes the growth or aggregation of the reinforcing particles, and ultimately leads to the large size range span and uneven dispersion of the reinforcing particles.

[0012] The reaction process releases a large amount of gas (KBF4=KF+BF3↑, K2TiF6=2KF+TiF4↑), which is one of the important reasons for the low yield of TiB2 particles. The higher the reaction temperature, the more intense the above reactions (KBF4=KF+BF3↑, K2TiF6=2KF+TiF4↑), leading to the lower yield of TiB2.

[0013] During the reaction process, the molten salt inevitably enters the interior of the melt, leading to the increase of the viscosity of the melt. The conventional method generally carries out the purification treatment of the melt before pouring. In fact, alloying will further increase the viscosity of the melt, leading to the increase of the difficulty of the purification treatment of the melt.

[0014] Further improve the controllable degree of the reaction process, obtain the size, morphology consistent, dispersion uniform nanometer reinforced particles and pure melt is the problem that the research and technical personnel in the field strive to solve. SUMMARY

[0015] In order to solve the problems existing in the prior art, the application provides a low-temperature in-situ synthesis of nanoparticle reinforced aluminum matrix composite material preparation method.

[0016] The technical scheme adopted by the application to solve its technical problems is:

[0017] The application provides a low-temperature in-situ synthesis of nanoparticle reinforced aluminum matrix composite material preparation method, which specifically comprises the following steps:

[0018] S1: Put the raw material AlSi12 eutectic alloy with a weight of m1 into a crucible with a diameter of D and melt, after melting, heat to a certain temperature and keep warm, and stir the eutectic alloy melt after keeping warm;

[0019] S2: Add the mixed salt of potassium fluotitanate and potassium fluoborate to the melt reaction, after the mixed salt is completely melted, slowly add AlSi12 eutectic alloy blocks with a weight of m2 to the melt;

[0020] S3: After the reaction is completed, slagging is carried out, and the melt is subjected to vacuum desalting treatment;

[0021] S4: The melt is subjected to temperature rising treatment, and pure aluminum ingots with a weight of m3 are added, then the temperature is controlled and pure magnesium with a weight of m4 is added;

[0022] S5: The melt is refined by argon rotary spraying method, the temperature is adjusted and pouring is carried out.

[0023] Preferably, the diameter D of the crucible, the total weight m of the prepared composite material and the mass fraction of TiB2 nanoparticles contained in the prepared composite material satisfy the following relationship:

[0024]

[0025] Wherein:

[0026] D is the diameter of the crucible;

[0027] m is the total weight of the prepared composite material, and the unit is g;

[0028] w t is the designed content of TiB2, which is a percentage;

[0029] γ Ti is the preset yield of Ti in K2TiF6, which is 100% in the application;

[0030] γ B is the preset yield of B in KBF4, and in the present application, 100% is taken;

[0031] W K2TiF6 is the relative molecular weight of K2TiF6;

[0032] W TiB2 is the molecular weight of TiB2;

[0033] W KBF4 is the molecular weight of KBF4;

[0034] ρ 盐 is the density of the molten mixed salt, in g / cm3; 3

[0035] h 盐 is the depth of the molten mixed salt, and according to actual production, the value is not more than 3 cm.

[0036] Preferably, in step S1, the temperature of the heating is 590-610℃.

[0037] Preferably, in step S2, the mixed salt of potassium fluotitanate and potassium fluoborate is preheated at 400℃ for 2h; the mixed salt of potassium fluotitanate and potassium fluoborate is added into the melt for reaction, and in the reaction process, AlSi12 eutectic alloy blocks with a weight of m2 are slowly added into the melt, and the temperature of the melt in the reaction process is controlled to be not more than 650℃; the weight m2 of the added AlSi12 eutectic alloy blocks is 5-10% of the weight of the added mixed salt.

[0038] Preferably, in step S3, the conditions for the vacuum salt removal treatment are as follows: the temperature of the melt is 600-630℃, the pressure is not more than 500Pa, and the vacuum salt removal treatment time is 15-30min.

[0039] Preferably, in step S4, the temperature of the melt is raised to 760-780℃ before the pure aluminum ingot is added; and before the pure magnesium is added, the temperature of the melt is controlled to be 700-720℃.

[0040] Preferably, in step S5, the rotating speed of the argon gas rotary spraying method is 300-600r / min, the pressure of the argon gas is 1-2MPa, and the refining time of the argon gas rotary spraying method is 15-25min.

[0041] The present application also provides a nanoparticle reinforced aluminum matrix composite material prepared by the above preparation method.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] ​(1) The present application first discloses that the depth of the molten salt in the reaction process is limited to be no more than 3 cm. In order to meet this requirement, the diameter of the crucible needs to be designed according to the content of the reinforcing particles in the composite material and the total weight of the prepared composite material. According to the calculation method proposed in the present application, under the premise of the same initial melting amount, the cross-sectional area of the crucible used in the present application is 4-9 times that of the traditional crucible, and the diameter is about 2-3 times that of the traditional crucible. Increasing the diameter of the crucible has three benefits: first, increasing the contact area of the metal melt and the molten salt improves the reaction efficiency; second, increasing the diffusion distance of the reaction products is beneficial to the dispersion of the reaction products; third, increasing the heat dissipation area is beneficial to the conduction of the heat released during the reaction, avoiding the rapid increase of the reaction temperature, and is beneficial to obtaining reinforcing particles with high uniformity in size and morphology.

[0044] (2) The present application utilizes the low melting point of AlSi12 eutectic alloy. After melting AlSi12 with a weight of m1 and controlling the temperature to about 600℃, the reaction speed is effectively inhibited compared with the temperature in the prior art, avoiding the problem of poor consistency of the reaction products caused by the rapid reaction and the rapid increase of the local temperature of the melt. After the mixed salt is melted, AlSi12 eutectic alloy blocks with a weight of m2 are slowly added to the melt, further improving the controllability of the melt temperature during the reaction, which is beneficial to the stable and continuous reaction, thereby obtaining reinforcing particles with uniform size and morphology;

[0045] (3) After the reaction is completed, the present application performs vacuum salt removal treatment under reasonable electromagnetic stirring conditions. The free K + , H + , F - ions in the melt can quickly separate from the melt, thereby achieving the purpose of removing the residual molten salt in the melt, and also playing the role of degassing and deslagging. Removing the residual molten salt first, and then alloying the melt, can not only reduce the difficulty of melt purification, but also avoid the further reaction of the residual molten salt after the temperature is increased to a high level, which causes the reinforcing particles to continue to grow, thereby being beneficial to obtaining nano-reinforcing particles with uniform size and small size, and a pure alloy melt. BRIEF DESCRIPTION OF DRAWINGS

[0046] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the following drawings of which:

[0047] Figure 1 SEM detection result graph of the particle size and morphology of the nano-reinforcing particles of the TiB2 / ZL101A composite material with a TiB2 mass fraction of 3% prepared in Example 1.

[0048] Figure 2 SEM detection result graph of the particle size and morphology of the nano-reinforcing particles of the TiB2 / ZL114A composite material with a TiB2 mass fraction of 5% prepared in Example 2.

[0049] Figure 3 SEM detection result graph of nano-reinforced particle size and morphology of TiB2 / ZL101A composite material with 3wt.% TiB2 prepared in Example 1.

[0050] Figure 4 SEM detection result graph of nano-reinforced particle size and morphology of TiB2 / ZL114A composite material with 5wt.% TiB2 prepared in Example 4. DETAILED DESCRIPTION

[0051] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout the drawings denote the same or similar elements or elements having the same or similar functions. The embodiments described below by referring to the drawings are exemplary only, and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0052] Example 1

[0053] The present embodiment proposes a method for preparing a low-temperature in-situ synthesized nano-particle reinforced aluminum matrix composite (ZL101A-3wt.%TiB2), which specifically comprises the following steps:

[0054] S1: Calculate the crucible diameter D according to the following formula:

[0055]

[0056] Wherein:

[0057] m is the total weight of the prepared composite material;

[0058] w t is the designed content of TiB2, which is 3%;

[0059] γ Ti is the preset yield of Ti in K2TiF6, which is 100%;

[0060] γ B is the preset yield of B in KBF4, which is 100%;

[0061] W K2TiF6 is the relative molecular weight of K2TiF6, which is 240.07;

[0062] W TiB2 is the relative molecular weight of TiB2, which is 69.49;

[0063] W KBF4 is the relative molecular weight of KBF4, which is 125.91;

[0064] The density of the molten mixed salt is 2.2 g / cm 3 ;

[0065] The depth of the molten mixed salt is 3 cm.

[0066] In this embodiment, 100 kg of ZL101A-3wt.%TiB2 composite material is prepared, so m = 100 kg = 1 x 10 5 kg of ZL101A-3wt.%TiB2 composite material, 11.4 kg of potassium fluotitanate salt, 11.0 kg of potassium fluoroborate salt, 58.4 kg (m) of AlSi12 eutectic alloy, 38.0 kg (m3) of pure Al, and 0.45 kg (m4) of pure Mg are needed. m2 is 5% of the weight of the mixed salt, i.e. m2 = 1.1 kg. Then, m1 = m - m2 = 57.3 kg.

[0067] The crucible diameter is calculated to be 65 cm by substituting the above parameters into the formula. The 57.3 kg of AlSi12 eutectic alloy is loaded into a crucible with a diameter of 65 cm, melted, and then heated to 600 °C and kept at this temperature. The eutectic alloy melt after keeping is stirred uniformly;

[0068] S2: The 400 °C preheated 2 h potassium fluotitanate and potassium fluoroborate mixed salt is added to the melt. After the mixed salt is completely dissolved in the melt, 1.1 kg of AlSi12 eutectic alloy blocks are slowly added to the melt while the temperature of the melt is controlled to be not more than 650 °C.

[0069] S3: After the reaction is completed, slagging is performed, and the melt is subjected to 20 min of vacuum desalting treatment. The temperature of the melt is controlled to be 615 °C and the pressure is controlled to be 500 Pa during the treatment.

[0070] S4: The melt is heated to 770 °C, 38.0 kg of pure Al ingot is added, and then the temperature is controlled to be 710 °C and 0.45 kg of pure Mg is added.

[0071] S5: The melt is refined by argon gas rotary spraying method. The rotation speed is 450 r / min, the pressure of argon gas is 1.5 MPa, and the time of argon gas rotary spraying method refining is 20 min. The temperature is adjusted and pouring is performed to obtain TiB2 / ZL101A composite material with 3% of TiB2 by mass fraction, and the morphology thereof is shown in Figure 1 .

[0072] The TiB2(3wt.%) / ZL101A aluminum matrix composite prepared in this embodiment has TiB2particle size concentrated in 90-100 nm. After T6 heat treatment according to HB 962-2001 and room temperature tensile test according to GB / T 228-2002, the average tensile strength of the composite prepared in one batch is 340 MPa, the average yield strength is 260 MPa, and the average elongation is 7%.

[0073] Example Two

[0074] This embodiment proposes a method for preparing a low-temperature in-situ synthesized nanoparticle reinforced aluminum matrix composite (ZL114A-5wt.%TiB2), which specifically comprises the following steps:

[0075] S1: Calculate the crucible diameter D according to the following formula:

[0076]

[0077] Wherein:

[0078] m is the total weight of the prepared composite;

[0079] w t is the designed content of TiB2, which is 5wt%;

[0080] γ Ti is the preset yield of Ti in K2TiF6, which is 100%;

[0081] γ B is the preset yield of B in KBF4, which is 100%;

[0082] W K2TiF6 is the relative molecular weight of K2TiF6, which is 240.07;

[0083] W TiB2 is the relative molecular weight of TiB2, which is 69.49;

[0084] W KBF4 is the relative molecular weight of KBF4, which is 125.91;

[0085] ρsaltis the density of the melted mixed salt, which is 2.2 g / cm 3 ;

[0086] h saltis the depth of the melted mixed salt. According to the actual production situation, the value is not greater than 3 cm, and here it is taken as 2.5 cm.

[0087] This embodiment prepares 100 kg of ZL114A-5wt.%TiB2composite, so m = 100 kg = 1 × 10 5g, for preparing 100 kg of ZL114A-5wt.%TiB2 composite, 17.3 kg of potassium fluotitanate salt, 18.1 kg of potassium fluoborate salt, 58.4 kg of AlSi12 eutectic alloy (m), 36.0 kg of pure Al (m3), and 0.7 kg of pure Mg (m4) are needed. m2 is 10% of the weight of the mixed salt, i.e. m2 = 3.5 kg. Then, ml = m - m2 = 54.9 kg.

[0088] According to the above formula, the diameter of the crucible is calculated to be 90 cm. The raw material AlSi12 eutectic alloy with a weight of 54.9 kg is loaded into the crucible with a diameter of 90 cm for melting. After melting, the temperature is raised to 600 °C and kept for a certain time. The eutectic alloy melt after keeping is stirred uniformly;

[0089] S2: The mixed salt of potassium fluotitanate and potassium fluoborate preheated at 400 °C for 2 h is added to the melt. After the mixed salt is completely dissolved in the melt, AlSi12 eutectic alloy blocks with a weight of 3.5 kg are slowly added to the melt while the temperature of the melt is controlled to be no more than 650 °C;

[0090] S3: After the reaction is completed, slagging is performed, and the melt is subjected to vacuum desalting treatment for 20 min. The temperature of the melt is controlled to be 615 °C and the pressure is 500 Pa during the treatment;

[0091] S4: The temperature of the melt is raised to 770 °C, and then pure aluminum ingot with a weight of 36.0 kg is added. Subsequently, the temperature is controlled to be 710 °C and pure magnesium with a weight of 0.7 kg is added;

[0092] S5: The melt is subjected to refining treatment by argon gas rotary spraying method. The rotating speed is 450 r / min, the pressure of argon gas is 1.5 MPa, and the time of argon gas rotary spraying method refining is 20 min. The temperature is adjusted and pouring is performed to obtain TiB2 / ZL114A composite nano-reinforced particles with a mass fraction of 5% of TiB2. The morphology diagram is shown in FIG. 1. Figure 2

[0093] The TiB2(5wt.%) / ZL114A aluminum matrix composite prepared in this embodiment has TiB2 particle size concentrated in 90-100 nm. After T6 heat treatment according to HB 962-2001, and room temperature tensile test according to GB / T 228-2002, the average tensile strength of the single-prepared composite is 395 MPa, the average yield strength is 325 MPa, and the average elongation is 6%.

[0094] Example Three

[0095] This embodiment proposes a method for preparing low-temperature in-situ synthesized nano-particle reinforced aluminum matrix composite (ZL101A-3wt.%TiB2). The method specifically includes the following steps:

[0096] ​S1: Put the raw material AlSi12 eutectic alloy with a weight of 57.3 kg into a crucible with a diameter of 30 cm to melt, and then heat to 600 ℃ and keep the temperature, and then stir the eutectic alloy melt after keeping the temperature;

[0097] S2: Put the mixed salt of potassium fluotitanate and potassium fluoborate preheated at 400 ℃ for 2 h into the melt, and then slowly add AlSi12 eutectic alloy blocks with a weight of 1.1 kg into the melt while controlling the temperature of the melt to be not higher than 650 ℃ after the mixed salt is completely dissolved in the melt;

[0098] S3: After the reaction is completed, slagging is carried out, and the melt is subjected to vacuum desalting treatment for 20 min, and the temperature of the melt is controlled to be 615 ℃ and the pressure is 500 Pa during the treatment;

[0099] S4: Heat the melt to 770 ℃, add pure aluminum ingot 38 kg, and then control the temperature to 710 ℃ and add pure magnesium 0.45 kg;

[0100] S5: The melt is refined by argon rotary spraying method, the rotating speed is 450 r / min, the pressure of argon is 1.5 MPa, and the refining time of argon rotary spraying method is 20 min; adjust the temperature and pour to obtain TiB2 / ZL101A composite material with a mass fraction of 3% of TiB2 nano-enhanced particles, and the morphology diagram is shown in Figure 3 .

[0101] The TiB2(3wt.%) / ZL101A aluminum matrix composite material prepared in this example has TiB2 particle size concentrated in 90-100 nm, and a large number of TiB2 phases with a size close to 2 μm are observed on the SEM photos. After T6 heat treatment according to HB 962-2001, and room temperature tensile test method according to GB / T 228-2002, the average tensile strength of the single-prepared composite material is 315 MPa, the average yield strength is 240 MPa, and the average elongation is 4%.

[0102] The TiB2 / ZL101A composite material with a mass fraction of 3% of TiB2 nano-enhanced particles prepared in Example One and Example Three is prepared under the same experimental conditions except for the diameter of the crucible. Figure 1 and Figure 3 It can be observed that Figure 1 , that is, the nano-enhanced particles prepared in Example One have better dispersity, and the particle size is more uniform, because the increase of the cross-sectional area of the crucible is beneficial to the dispersion of the reaction products, and at the same time, the increase of the heat dissipation area is beneficial to the conduction of the heat released by the reaction, and the enhanced particles with high consistency in morphology and size are obtained.

[0103] Example Four

[0104] The embodiment provides a method for in-situ synthesis of low-temperature nanoparticle reinforced aluminum matrix composite (ZL114A-5wt.%TiB2), and specifically comprises the following steps.

[0105] S1: The diameter D of the crucible is calculated according to the following formula:

[0106]

[0107] Wherein:

[0108] D is the diameter of the crucible;

[0109] m is the total weight of the prepared composite material;

[0110] w t The designed content of TiB2 is 5wt.%;

[0111] γ Ti The preset yield of Ti in K2TiF6 is 100%;

[0112] γ B The preset yield of B in KBF4 is 100%;

[0113] W K2TiF6 The relative molecular weight of K2TiF6 is 240.7;

[0114] W TiB2 The relative molecular weight of TiB2 is 69.49;

[0115] W KBF4 The molecular weight of KBF4 is 125.91;

[0116] ρsalt is the density of the melted mixed salt, and is 2.2g / cm 3 ;

[0117] h salt is the depth of the melted mixed salt, and the value is not greater than 3cm according to the actual production, and is 2.5cm here.

[0118] The embodiment prepares 100kg of ZL114A-5wt.%TiB2 composite material, so m=100kg=1×10 5 kg, and the preparation of 100kg of ZL101A-5wt.%TiB2 composite material requires 17.3kg of potassium fluotitanate, 18.1kg of potassium fluoroborate, 58.4kg (m) of AlSi12, 36.0kg (m3) of pure Al, and 0.7kg (m4) of pure Mg.

[0119] The diameter of the crucible was calculated to be 90 cm by the above formula. The raw material AlSi12 eutectic alloy with a weight of 58.4 kg was loaded into the crucible with a diameter of 90 cm for melting. After melting, the temperature was raised to 600°C and kept constant, and the eutectic alloy melt after keeping constant was stirred uniformly;

[0120] S2: The mixed salt of potassium fluotitanate and potassium fluoroborate preheated at 400°C for 2 h was added to the melt, and after the mixed salt was completely dissolved in the melt, the melt was stirred for 20 min at a temperature of 615°C and a pressure of 500 Pa;

[0121] S3: After the reaction was completed, slagging was performed, and the melt was subjected to vacuum desalting treatment for 20 min. The temperature of the melt was controlled to be 615°C, and the pressure was controlled to be 500 Pa during the treatment;

[0122] S4: The melt was heated to 770°C, and pure aluminum ingot 36.0 kg was added, followed by controlling the temperature to 710°C and adding pure magnesium 0.7 kg;

[0123] S5: The melt was refined by argon rotary spraying method, the rotation speed was 450 r / min, the pressure of argon was 1.5 MPa, and the refining time of the argon rotary spraying method was 20 min. The temperature was adjusted and pouring was performed, and TiB2 / ZL114A composite material nano-enhanced particles with a mass fraction of 5% of TiB2 were obtained, and the morphology diagram thereof is shown in Figure 4 .

[0124] The TiB2(5wt.%) / ZL114A aluminum matrix composite material prepared in this example has a large amount of TiB2 particles with a size of 400-800 nm. After T6 heat treatment according to HB 962-2001, and room temperature tensile test method according to GB / T 228-2002, the average tensile strength of the single-prepared composite material is 360 MPa, the average yield strength is 315 MPa, and the average elongation is 4%.

[0125] The TiB2 / ZL114A composite material nano-enhanced particles with a mass fraction of 5% of TiB2 prepared in Example Four were prepared under the same experimental conditions as those in Example Two, except that no Al-Si eutectic alloy block was added to the melt for temperature reduction in Example Four. Figure 2 and Figure 4 It can be observed that the nano-enhanced particles prepared in Example Four form a large number of clusters, and the dispersion effect and uniformity are far inferior to those of the nano-enhanced particles prepared in Example Two. This is because the process of adding Al-Si eutectic alloy block for temperature reduction further improves the controllability of the melt temperature during the reaction, so that the reaction continues stably, thereby obtaining uniform and consistent enhanced particles in morphology and size.

[0126] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely divergences of the principles and application of the present application and that numerous modifications, changes, substitutions, and alterations can be made thereto without departing from the spirit and scope of the present application, which is defined by the following claims and their equivalents.

Claims

1. A method for preparing low-temperature in-situ synthesized nanoparticle-reinforced aluminum matrix composites, characterized in that, Specifically, the following steps are included: S1: The raw material AlSi12 eutectic alloy with a weight of m1 is placed into a crucible with a diameter of D and melted. After melting, the temperature is raised to a certain temperature and held. The eutectic alloy melt after holding is stirred evenly. S2: Add the mixed salt of potassium fluorotitanate and potassium fluoroborate to the melt for reaction. After the mixed salt has completely melted, slowly add an AlSi12 eutectic alloy block with a weight of m2 to the melt. S3: After the reaction is complete, remove the slag and perform vacuum desalination on the melt; S4: Heat the melt, add pure aluminum ingots with a weight of m3, then control the temperature and add pure magnesium with a weight of m4. S5: The melt is refined using the argon rotary jet method, the temperature is adjusted, and then it is poured. The crucible diameter D, the total weight m of the prepared composite material, and the mass fraction of TiB2 nanoparticles in the prepared composite material conform to the following relationship: in: D is the diameter of the crucible; m is the total weight of the prepared composite material; w t The design content of TiB2; γ Ti The preset yield of Ti in K2TiF6; γ B This is the preset yield of B in KBF4; W K2TiF6 The relative molecular weight of K2TiF6; W TiB2 This represents the relative molecular weight of TiB2. W KBF4 This represents the relative molecular weight of KBF4. ρ 盐 The density of the molten mixed salt; h 盐 The depth of the molten mixed salt should not exceed 3 cm, depending on actual production conditions.

2. The method for preparing a low-temperature in-situ synthesized nanoparticle-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step S1, the temperature for heating is 590–610°C.

3. The method for preparing a low-temperature in-situ synthesized nanoparticle-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step S2, the potassium fluorotitanate and potassium fluoroborate mixed salt is preheated at 400°C for 2 hours; the potassium fluorotitanate and potassium fluoroborate mixed salt is added to the melt for reaction, and during the reaction, an AlSi12 eutectic alloy block with a weight of m2 is slowly added to the melt, controlling the melt temperature to not exceed 650°C during the reaction; the weight m2 of the added AlSi12 eutectic alloy block is 5-10% of the weight of the added mixed salt.

4. The method for preparing a low-temperature in-situ synthesized nanoparticle-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step S3, the conditions for vacuum desalination are: the temperature of the melt is 600-630℃, the pressure is not greater than 500Pa, and the vacuum desalination time is 15-30min.

5. The method for preparing a low-temperature in-situ synthesized nanoparticle-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step S4, the temperature of the melt is raised to 760-780°C before adding pure aluminum ingots; the temperature of the melt is controlled to 700-720°C before adding pure magnesium.

6. The method for preparing a low-temperature in-situ synthesized nanoparticle-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step S5, the rotation speed of the argon gas rotary jet method is 300-600 r / min, the pressure of the argon gas is 1-2 MPa, and the refining time of the argon gas rotary jet method is 15-25 min.

7. A nanoparticle-reinforced aluminum-based composite material, prepared by the preparation method according to any one of claims 1-6.

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