A lightweight, high-strength, high-toughness, and high-modulus Al-Mg-Yb-Zr-TiB2 composite material, its preparation method, and application

Abstract

The present invention discloses a lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material, its preparation method and application. The material comprises the following components by mass percentage: Mg: 3.0-10.0%; Yb: 0.2-3.0%; Zr: 0.2-1.5%; TiB2: 2.0-15.0%; the balance is Al and inevitable impurities. The present invention prepares an aluminum matrix composite ingot through ultrasonic casting combined with a fluoride salt reaction, further atomizes the powder, and finally performs additive manufacturing. A large number of hexagonal columnar multi-component second-phase particles which are dispersedly distributed and have good wettability with the matrix exist in the matrix of the prepared aluminum matrix composite material. The present invention has advantages in both composition design and process design, and meets the requirements of new-generation industrial machines, transportation and electronic packaging and other fields.

Description

Technical Field

[0001] The present invention relates to a lightweight, high-strength, high-toughness and high-modulus aluminum matrix composite material, a preparation method and an application thereof, and particularly relates to a reinforced Al-Mg-Yb-Zr-TiB2 composite material with multi-component second-phase particles, belonging to the technical field of new materials for additive manufacturing. Background Art

[0002] Aluminum matrix composites have high specific strength, excellent fatigue performance and extremely high elastic modulus, and are often used in fields such as industrial machinery, transportation and electronic packaging. They are extremely important engineering application materials. In recent years, additive manufacturing technology has developed rapidly. Its process characteristics are mainly rapid cooling, which is beneficial to obtaining fine grains, thereby improving the performance of alloys. Aluminum matrix composites with excellent performance and complex structures can be prepared by additive manufacturing.

[0003] The non-metallic reinforcement phases in aluminum matrix composites mainly include ZrO2, AlN, TiC, TiB2, etc. Among them, the strengthening effect of adding TiB2 particles to the aluminum matrix is the most significant. A large number of nano-scale TiB2 particles can be formed in the aluminum matrix by the method of reacting with fluoride salts (K2TiF6 and KBF4), but there will be a phenomenon of particle agglomeration. Especially after adding a high volume fraction of TiB2 particles, the material properties are greatly deteriorated. The yield strength and ultimate tensile strength of the 5TiB2 / Al-4.5Cu (mass fraction) composite material prepared by the mixed salt reaction method are 219 MPa and 354 MPa respectively. At present, some studies have shown that the method of electromagnetic stirring can play a role in improving the dispersion of TiB2 particles, but it will deteriorate the interfacial bonding between TiB2 particles and the aluminum matrix.

[0004] Al-5Ti-B alloy is the most widely used grain refiner in industry at present. A large number of TiB2 particles in this master alloy will have an activity gradient during the melting process. The interface between TiB2 particles and the aluminum melt will adsorb excess Ti atoms, thereby forming an Al3Ti outer shell layer. And Al3Ti has good lattice matching with TiB2 particles, and at the same time Al3Ti also has good lattice matching with the aluminum matrix. This indicates that the existence of the Al3Ti outer shell layer improves the interfacial relationship between TiB2 particles and the aluminum matrix. However, the Al-5Ti-B alloy produced by traditional casting has coarse grains, and the second-phase particles are generally distributed at the grain boundaries, and there is still a problem of particle segregation.

[0005] Due to the relatively high melting point of the TiB2 ceramic reinforcement phase, traditional processing and forming methods (such as squeeze casting, stir casting, and melt infiltration) cannot provide sufficient temperature conditions, resulting in insufficient melting of ceramic particles. This leads to poor wettability and poor interfacial bonding between the TiB2 reinforcement phase and the matrix, making it inconvenient to prepare complex-shaped parts. Selective laser melting forming technology uses laser as the energy input source. By adjusting the laser power, the forming temperature can reach 2000 - 3000K, which is more conducive to the interfacial bonding between the matrix and TiB2 particles. Combining the advantages of additive manufacturing and optimizing the second-phase particles by composition to improve the distribution of TiB2 particles, it is expected to prepare aluminum matrix composites with more excellent properties. Therefore, it is very necessary to develop this method. Summary of the Invention

[0006] Based on Patent 2023109078320, this invention conducts research aiming at how to uniformly introduce an appropriate amount of TiB2 particles and simultaneously possess the characteristics of light weight, high strength, high toughness, and high modulus, thus forming this invention.

[0007] The purpose of this invention is to solve the problems that TiB2 particles in aluminum matrix composites are prone to agglomeration and have poor bonding with the aluminum matrix, and to provide a lightweight, high-strength, high-toughness, and high-modulus Al-Mg-Yb-Zr-TiB2 composite material and its preparation method to meet the needs of high-performance materials in key fields such as industrial machinery, transportation, and electronic packaging.

[0008] A lightweight, high-strength, high-toughness, and high-modulus Al-Mg-Yb-Zr-TiB2 composite material of this invention includes the following components by mass percentage:

[0009] Mg: 3.0 - 10.0%, preferably 3.5 - 8.0%, more preferably 4.0 - 6.0%;

[0010] Yb: 0.2 - 3.0%, preferably 0.2 - 1.0%, more preferably 0.3 - 0.5%;

[0011] Zr: 0.2 - 1.5%, preferably 0.3 - 1.0%, more preferably 0.3 - 0.6%;

[0012] TiB2: 2.0 - 15.0%, preferably 3.0 - 10.0%, more preferably 3.0 - 6.0%, even more preferably 4.0 - 5.0%;

[0013] The balance is Al and unavoidable impurities.

[0014] Preferably, the microstructure of the Al-Mg-Yb-Zr-TiB2 composite mainly consists of an α-Al matrix, spherical Al3(Yb,Zr) dispersed therein, and hexagonal columnar multi-component second-phase particles. The inner shell layer of the multi-component second-phase particles is composed of nanoscale TiB2 particles, and the outer shell layer is the Al3(Yb,Zr,Ti) phase.

[0015] As a further preference, the size of the multi-component hexagonal columnar second-phase particles is 10 - 30 nm, the size of the spherical Al3(Yb,Zr) particles is 20 - 200 nm, and the matrix grain size is equiaxed grains with a size of 2 - 6 μm.

[0016] The density of the Al-Mg-Yb-Zr-TiB2 composite is 2.6 - 2.76 g·cm -3 。

[0017] A method for preparing a lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite according to the present invention includes the following steps: allocating raw materials according to the designed composition, and preparing an ingot by ultrasonic casting; obtaining Al-Mg-Yb-Zr-TiB2 composite powder after gas atomization of the ingot; performing additive manufacturing on the Al-Mg-Yb-Zr-TiB2 composite powder to obtain the product. During ultrasonic casting, control the ultrasonic power to be greater than or equal to 600 W.

[0018] In the present invention, titanium boride is prepared by reacting K2TiF6 and KBF4 in an aluminum melt.

[0019] Preferably, the specific process of ultrasonic casting is as follows: heat the Al ingot to a molten state at 820 - 830 °C, then add the dried fluorine salt mixed powder into the aluminum melt using a bell jar. After the reaction is complete, scoop out the surface by-products and floating slag with a slag skimmer. After cooling to 750 - 760 °C, sequentially add the weighed Al-4Yb and Al-10Zr alloy blocks, stir until completely melted, insert the titanium alloy ultrasonic probe into the melt, with a power greater than or equal to 600 W, preferably 600 - 900 W, and an ultrasonic time of 5 - 10 min. After taking out the ultrasonic probe, let it stand for 2 - 3 min. Then press the Mg ingot wrapped in aluminum foil into the aluminum melt using a bell jar and keep it for 2 - 3 min. After stirring evenly, heat up to 730 - 750 °C, press the refining agent into the aluminum melt using a bell jar, vibrate up and down for 2 - 3 min, insert a degassing gun, introduce high-purity argon gas, and continue for 20 - 30 min. Take out the degassing gun, heat up to 730 - 750 °C and keep it warm for 20 - 30 min, then cool down to 700 - 710 °C, skim the slag and then perform pouring.

[0020] As a further preference, the fluorinated salt mixed powder is K2TiF6, KBF4 and Na3AlF6, the mass fraction of Ti and B is controlled at (2.15 - 2.25):1, the addition amount of Na3AlF6 is 5 - 8% of the total mass of the two fluorinated salt powders of K2TiF6 and KBF4, and the prepared powder is wrapped separately with aluminum foil.

[0021] As a further preference, a preparation method of an Al-Mg-Yb-Zr-TiB2 composite material with both light weight, high strength, high toughness and high modulus includes: preparation work, ultrasonic casting, atomization powder making and additive manufacturing, specifically including:

[0022] A. Preparation work:

[0023] 1) By mass percentage, it includes the following components: Mg: 3.0 - 10.0%; Yb: 0.2 - 3.0%; Zr: 0.2 - 1.5%; TiB2: 2.0 - 15.0%; the balance is Al and inevitable impurities;

[0024] 2) Weigh and prepare the fluorinated salt mixed powder, including 3 kinds of powders of K2TiF6, KBF4 and Na3AlF6, the mass fraction of Ti and B is controlled at (2.15 - 2.25):1, the addition amount of Na3AlF6 is 5 - 8% of the total mass of the two fluorinated salt powders of K2TiF6 and KBF4, and the prepared powder is wrapped separately with aluminum foil;

[0025] 3) Preheat the slag skimmer, graphite degassing gun and crucible at 700 - 720 °C for 3 - 4 h;

[0026] 4) Weigh Al blocks (purity 99.995%), Mg blocks (purity 99.95%), Al-4Yb alloy blocks (purity 99.9%) and Al-10Zr alloy blocks (purity 99.9%), wrap the refining agent with aluminum foil (the addition amount is 0.4 - 0.8% of the melt mass), and place the above together in an oven at 200 - 250 °C for drying for 1 - 2 h.

[0027] B. Ultrasonic casting

[0028] 1) Heat the Al ingot to the molten state at 820 - 830 °C, then add the dried fluorinated salt mixed powder into the aluminum melt with a bell jar. After the reaction is complete, use a slag skimmer to fish out the surface by-products and floating slag;

[0029] 2) After cooling to 750 - 760 °C, sequentially add the weighed Al-4Yb and Al-10Zr alloy blocks and stir until completely melted;

[0030] 3) Figure 1The titanium alloy ultrasonic device used in the present invention is shown. Insert the titanium alloy ultrasonic probe into the melt, with a power greater than or equal to 600 W, preferably 600 - 900 W, more preferably 600 - 820 W, and even more preferably 780 - 820 W. The ultrasonic time is 5 - 10 min. After taking out the ultrasonic probe, let it stand for 2 - 3 min;

[0031] 4) Then press the pure Mg ingot wrapped in aluminum foil into the aluminum melt with a bell jar and hold for 2 - 3 min. After stirring evenly, heat up to 730 - 750 °C, and press the refining agent into the aluminum melt with a bell jar, and vibrate up and down for 2 - 3 min;

[0032] 5) Insert the degassing gun, introduce high-purity argon gas, after 20 - 30 min, take out the degassing gun, heat up to 730 - 750 °C and keep warm for 20 - 30 min, then cool down to 700 - 710 °C, skim the slag and then carry out casting. The mold used for casting is an iron mold.

[0033] C. Atomization powder making

[0034] Cut the middle part of the ingot obtained by casting with a wire cutting machine, place it in an air atomization powder making machine to prepare powder, and sieve the prepared Al-Mg-Yb-Zr-TiB2 composite material powder. Select the fine powder with a mesh size of 200 as the powder for additive manufacturing of Al-Mg-Yb-Zr-TiB2 composite materials.

[0035] D. Additive manufacturing

[0036] The laser power of the additive manufacturing equipment is 200 - 450 W, the scanning speed is 300 - 1400 mm / s, the powder laying thickness is 0.03 - 0.06 mm, and the scanning spacing is 0.05 - 0.15 mm. The forming substrate is made of Al-Mg-Yb-Zr alloy, the preheating temperature of the substrate is 80 - 150 °C, and the scanning strategy during additive manufacturing is layer-by-layer laser scanning.

[0037] Through the coordination of the preparation process and components, the present invention ingeniously solves the problem that it is difficult to coordinate high modulus, high tensile strength and high elongation.

[0038] For the printed parts obtained by the present invention, their yield strength is greater than or equal to 420 MPa, tensile strength is greater than or equal to 490 MPa, elongation is greater than or equal to 2.4%, and elastic modulus is greater than or equal to 85 GPa. After optimization, for the obtained printed parts, their yield strength can reach 459 - 467 MPa, tensile strength is 515 - 541 MPa, elongation is 8.2 - 8.4%, and elastic modulus is 92.9 - 94.5 GPa.

[0039] The Al-Mg-Yb-Zr-TiB2 composite material obtained by the present invention can further expand the application of this type of aluminum-based composite material in fields such as industrial machinery, transportation and electronic packaging.

[0040] Beneficial technical effects brought by the technical solution of the present invention compared with the prior art:

[0041] 1) The preparation method of the Al-Mg-Yb-Zr-TiB2 composite material provided by the present invention has high operability and relatively low preparation cost.

[0042] 2) The present invention effectively further enhances the interfacial bonding between TiB2 particles and the aluminum matrix, and enhances the role of ceramic particles in the metal matrix composite material.

[0043] 3) The present invention effectively improves the distribution of TiB2 particles in the aluminum matrix. As Figure 2 shown, in the fluoride salt reaction stage of ultrasonic casting in the invention content, nano-scale TiB2 particles tend to agglomerate together. After adding Al-4Yb and Al-10Zr alloy blocks, the three elements Ti, Zr, and Yb will adsorb on the surface of TiB2 particles to form an Al3(Yb,Zr,Ti) phase shell, improving the interfacial bonding. And the increase in the size of the second-phase particles can improve the "nano-agglomeration effect" of TiB2 particles. After ultrasonic treatment, the distribution of the second phase will be further improved.

[0044] 4) The composition in the present invention has strong controllability. The three elements Ti, Zr, and Yb that fail to participate in the nucleation of the second phase can also exist in the aluminum matrix in the form of strengthening phases such as Al3Ti, Al3Zr, and Al3Yb.

[0045] 5) The present invention proposes a method for preparing Al-Mg-Yb-Zr-TiB2 composite materials using additive manufacturing technology, which is not only beneficial to the preparation of complex structural parts of aluminum matrix composite materials, but also the obtained printed products have the characteristics of light weight, high strength, high toughness, and high modulus. Brief Description of the Drawings

[0046] Figure 1 Schematic diagram of the equipment used for ultrasonic casting.

[0047] Figure 2 Schematic diagram of the distribution state, size, and composition change of the multi-component second phase in the Al-Mg-Yb-Zr-TiB2 composite material of the present invention during the preparation process.

[0048] Figure 3 Scanning electron microscope image of the Al-Mg-Yb-Zr-TiB2 composite material prepared in Example 3.

[0049] Figure 4 Multi-component hexagonal columnar second-phase particles in the Al-Mg-Yb-Zr-TiB2 composite material prepared in Example 3.

[0050] Figure 1 Among them, 1 is a titanium alloy ultrasonic probe; 2 is a transducer; 3 is a fixing plate; 4 is a stainless steel bracket; 5 is a resistance wire; 6 is a crucible; 7 is an aluminum melt; 8 is an adjustable bolt.

[0051] Figure 2 Among them, 9 is a TiB2 particle; 10 is an Al3(Yb,Zr) particle; 11 is a multi-component second-phase particle with an outer shell layer of Al3(Yb,Zr,Ti) phase and TiB2 particles inside.

[0052] From Figure 3 It can be seen that the microstructure of the obtained product is mainly composed of equiaxed α-Al matrix, dispersedly distributed second-phase spherical particles Al3(Yb,Zr), and hexagonal multi-component second-phase particles. Among them, the size of the multi-component hexagonal second-phase particles is 10 - 30 nm, the size of the spherical Al3(Yb,Zr) particles is 20 - 200 nm, and the grain size of the α-Al matrix is 2 - 6 μm.

[0053] From Figure 4 It can be seen that the inner shell layer of the multi-component hexagonal second-phase particles is nanoscale TiB2 particles, and the outer shell layer is Al3(Yb,Zr,Ti) phase. Specific Embodiments

[0054] For the convenience of understanding the present invention, the following will describe the present invention in a more comprehensive and detailed manner in combination with preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0055] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0056] Unless otherwise specified, various reagents and raw materials used in the present invention are all commercially available products or products that can be obtained by known methods.

[0057] Example 1

[0058] Ingredient by mass ratio: Mg: 5.0%, Yb: 0.4%, Zr: 0.3%, TiB2: 2.0%, and the rest is Al. First, heat the pure Al ingot to the molten state at 825 °C, then use a bell jar to add the dried fluoride salt mixed powder (the fluoride salt mixed powder is composed of three powders, K2TiF6, KBF4, and Na3AlF6, where the mass fraction of Ti and B is controlled at about 2.2:1, and the addition amount of Na3AlF6 is 6% of the total mass of the two fluoride salt powders, K2TiF6 and KBF4) into the aluminum melt. After the reaction is complete, use a slag skimming spoon to remove the surface by-products and scum. After cooling to 755 °C, add the weighed Al-4Yb and Al-10Zr alloy blocks in sequence, stir until completely melted, insert the titanium alloy ultrasonic probe into the melt, with a power of 800 W and an ultrasonic time of 8 min. After taking out the ultrasonic probe, let it stand for 2 min. Then, use a bell jar to press the pure Mg ingot wrapped in aluminum foil into the aluminum melt and keep it for 2 min. After stirring evenly, heat up to 740 °C, use a bell jar to press the refining agent into the aluminum melt, vibrate up and down for 2 min, insert the degassing gun, introduce high-purity argon gas, and after 25 min, take out the degassing gun, heat up to 740 °C and keep it warm for 25 min, then cool down to 705 °C, skim the slag and then pour. The mold used for pouring is an iron mold. Cut the middle part of the ingot obtained by pouring with a wire cutting machine, place it in a gas atomization powder making machine to prepare powder. Sieve the prepared Al-Mg-Yb-Zr-TiB2 composite material powder, and select the fine powder passing through 200 meshes as the powder for additive manufacturing of Al-Mg-Yb-Zr-TiB2 composite materials. The laser power of the additive manufacturing equipment is 310 W, the scanning rate is 1000 mm / s, the powder spreading thickness is 0.03 mm, and the scanning spacing is 0.1 mm. Use Al-Mg-Yb-Zr alloy as the forming substrate, with a substrate preheating temperature of 80 °C. The scanning strategy during the additive manufacturing process is layer-by-layer laser scanning. The sample performance parameters are shown in Table 1.

[0059] Example 2

[0060] This example is basically the same as Example 1, except that the mass fraction of TiB2 is 4.0%, and the sample performance parameters are shown in Table 1.

[0061] Example 3

[0062] This example is basically the same as Example 1, except that the mass fraction of TiB2 is 5.0%, and the sample performance parameters are shown in Table 1.

[0063] Example 4

[0064] This example is basically the same as Example 1, except that the content of TiB2 is 10%, and the sample performance parameters are shown in Table 1.

[0065] Example 5

[0066] This example is basically the same as Example 1, except that the mass fraction of TiB2 is 15.0%, and the sample performance parameters are shown in Table 1.

[0067] Example 6

[0068] This example is basically the same as Example 3, except that the power of the ultrasonic probe for titanium alloy during ultrasonic casting is 600 W, and the sample performance parameters are shown in Table 1.

[0069] Example 7

[0070] This example is basically the same as Example 3, except that the power of the ultrasonic probe for titanium alloy during ultrasonic casting is 700 W, and the sample performance parameters are shown in Table 1.

[0071] Comparative Example 1

[0072] This comparative example is basically the same as Example 3, except that the components are proportioned by mass ratio: Mg: 5.0%, TiB2: 5.0%, and the rest is Al, and the sample performance parameters are shown in Table 1.

[0073] Comparative Example 2

[0074] Other conditions are the same as those in Example 3, except that TiB2 is not added; the sample performance parameters are shown in Table 1.

[0075] Comparative Example 3

[0076] This comparative example is basically the same as Example 3, except that the content of TiB2 is 1.0%, and the sample performance parameters are shown in Table 1.

[0077] Comparative Example 4

[0078] This comparative example is basically the same as Example 3, except that the content of TiB2 is 17.0%, and the sample performance parameters are shown in Table 1.

[0079] Comparative Example 5

[0080] This comparative example is basically the same as Example 3, except that the national standard ZL205A alloy is selected as the matrix and 5.0% mass fraction of TiB2 is added, and the sample performance parameters are shown in Table 1.

[0081] Comparative Example 6

[0082] This comparative example is basically the same as Example 3, except that the national standard ZL101A alloy is selected as the matrix and 5.0% mass fraction of TiB2 is added, and the sample performance parameters are shown in Table 1.

[0083] Comparative Example 7

[0084] This comparative example is basically the same as Example 3, except that the power of the titanium alloy ultrasonic probe during ultrasonic casting is 300 W, and the sample performance parameters are shown in Table 1.

[0085] Comparative Example 8

[0086] This comparative example is basically the same as Example 3, except that the sample obtained by ultrasonic casting is the final sample, without atomization powder making and additive manufacturing, and the sample performance parameters are shown in Table 1.

[0087] Table 1 Sample performance parameters

[0088]

[0089]

[0090] It should be noted that Comparative Example 1 shows that the addition of Zr and Yb can improve the wettability between TiB2 and the Al matrix, thereby improving the sample performance; Comparative Examples 2, 3 and 4 show that the lack of reinforcing phase particles will occur when TiB2 is not added or the mass fraction of added TiB2 is less than 2.0%, while when it is higher than 15.0%, it will increase the difficulty of ultrasonic casting. For the fluorine salt reaction method adopted in the present invention, the mass fraction is optimal at 5.0%; in Comparative Example 5, ZL205A is an Al-Cu series casting alloy, which has relatively high strength itself, but due to the problem of specific gravity segregation of Cu, excellent composite materials cannot be obtained in the system of the present invention, and at the same time its density is relatively large and its application is limited; in Comparative Example 6, ZL101A is an Al-Si-Mg alloy with good casting fluidity and moderate strength, but Si in it will be "poisoned" with Zr in the present invention, and excellent composite materials cannot be obtained in the system of the present invention; in Comparative Example 7, the ultrasonic effect with low power has a poor dispersion effect on TiB2 particles; in Comparative Example 8, without atomization powder making and additive manufacturing, the obtained ingot has coarse grains, and the existence of a small amount of casting defects itself also makes its tissue compactness poor. The alloy system and preparation process adopted in the present invention can prepare aluminum matrix composite materials with light weight, high strength, high toughness and high modulus, which have great advantages and application prospects.

Claims

1. A lightweight, high-strength, high-toughness, and high-modulus Al-Mg-Yb-Zr-TiB2 composite material, characterized in that: The lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material comprises the following components by mass percentage: Mg: 3.0 - 10.0%; Yb: 0.2 - 3.0%; Zr：0.2～1.5%； TiB2: 2.0 - 15.0%; The balance is Al and inevitable impurities; The lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material is prepared by the following steps: Raw materials are allocated according to the designed composition, and an ingot is prepared by ultrasonic casting; after the ingot is gas atomized into powder, Al-Mg-Yb-Zr-TiB2 composite material powder is obtained; the Al-Mg-Yb-Zr-TiB2 composite material powder is subjected to additive manufacturing to obtain the product. During ultrasonic casting, the ultrasonic power is controlled to be greater than or equal to 600W; The process of the ultrasonic casting is as follows: the Al ingot is heated to the molten state at 820 - 830 °C, and then the dried fluoride salt mixed powder is added into the aluminum melt by a bell jar. After the reaction is complete, the surface by-products and floating slag are fished out with a slag skimming spoon. After cooling to 750 - 760 °C, the weighed Al-4Yb and Al-10Zr alloy blocks are added in sequence, and stirred until completely melted. The titanium alloy ultrasonic probe is inserted into the melt, with the power greater than or equal to 600W, and the ultrasonic time is 5 - 10 min. After taking out the ultrasonic probe, it is left to stand for 2 - 3 min. Then the Mg ingot wrapped with aluminum foil is pressed into the aluminum melt by a bell jar and kept for 2 - 3 min. After stirring evenly, it is heated to 730 - 750 °C, and the refining agent is pressed into the aluminum melt by a bell jar and vibrated up and down for 2 - 3 min. The degassing gun is inserted, and high-purity argon gas is introduced for 20 - 30 min. After taking out the degassing gun, it is heated to 730 - 750 °C and kept warm for 20 - 30 min, and then cooled to 700 - 710 °C. After slag skimming, pouring is carried out; The fluoride salt mixed powder is K2TiF6, KBF4 and Na3AlF6, the mass fraction of Ti and B is controlled at (2.15 - 2.25):1, and the addition amount of Na3AlF6 is 5 - 8% of the total mass of the two fluoride salt powders of K2TiF6 and KBF4. The prepared powder is wrapped separately with aluminum foil; The microstructure of the Al-Mg-Yb-Zr-TiB2 composite material mainly consists of an α-Al matrix, spherical Al3(Yb,Zr) dispersed distribution and hexagonal columnar multi-component second-phase particles. Among them, the inner shell layer of the multi-component second-phase particles is nanoscale TiB2 particles, and the outer shell layer is Al3(Yb,Zr,Ti) phase.

2. A lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material according to claim 1, characterized in that: The size of the multi-component hexagonal columnar second-phase particles is 10 - 30 nm, the size of the spherical Al3(Yb,Zr) particles is 20 - 200 nm, and the matrix grain size is equiaxed grains of 2 - 6 μm.

3. A lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material according to claim 1, characterized in that: The lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material comprises the following components by mass percentage: Mg: 3.5 - 8.0%; Yb: 0.2 - 1.0%; Zr：0.3～1.0%； TiB2: 3.0 - 10.0%; The balance is Al and inevitable impurities.

4. A lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material according to claim 3, characterized in that: The lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material comprises the following components by mass percentage: Mg: 4.0 - 6.0%; Yb: 0.3 - 0.5%; Zr：0.3～0.6%； TiB2: 3.0 - 6.0%; The balance is Al and unavoidable impurities.

5. A lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material according to claim 4, characterized in that: The lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material comprises the following components by mass percentage: Mg: 4.0 - 6.0%; Yb: 0.3 - 0.5%; Zr：0.3～0.6%； TiB2: 4.0 - 5.0%; The balance is Al and unavoidable impurities.

6. A lightweight, high-strength, high-toughness, and high-modulus Al-Mg-Yb-Zr-TiB2 composite material according to claim 1, characterized in that: The density of the Al-Mg-Yb-Zr-TiB2 composite material is 2.6 to 2.76 g·cm -3 .

7. A lightweight, high-strength, high-toughness and high-modulus Al-Mg-Yb-Zr-TiB2 composite material according to claim 1, characterized in that: The preparation method includes: preparatory work, ultrasonic casting, atomization powder making and additive manufacturing, specifically including: A. Preparatory work: 1) Comprises the following components by mass percentage: Mg: 3.0 - 10.0%; Yb: 0.2 - 3.0%; Zr: 0.2 - 1.5%; TiB2: 2.0 - 15.0%; the balance is Al and unavoidable impurities; 2) Weigh and prepare a fluoride salt mixed powder, including three kinds of powders, namely K2TiF6, KBF4 and Na3AlF6. The mass fraction of Ti and B is controlled at (2.15 - 2.25): 1, and the addition amount of Na3AlF6 is 5 - 8% of the total mass of the two fluoride salt powders K2TiF6 and KBF4. The prepared powder is wrapped separately with aluminum foil; 3) Preheat the slag skimmer, graphite degassing gun and crucible at 700 - 720 °C for 3 - 4 h; 4) Weigh the Al block, Mg block, Al-4Yb alloy block and Al-10Zr alloy block. Wrap the refining agent with aluminum foil and place the above-mentioned together in an oven at 200 - 250 °C for drying for 1 - 2 h; the addition amount of the refining agent is 0.4 - 0.8% of the melt mass; B. Ultrasonic casting 1) Heat the Al ingot to the molten state at 820 - 830 °C, then add the dried fluoride salt mixed powder into the aluminum melt with a bell jar. After the reaction is complete, scoop out the surface by-products and floating slag with a slag skimmer; 2) After cooling to 750 - 760 °C, add the weighed Al-4Yb and Al-10Zr alloy blocks in sequence and stir until completely melted; 3) Insert the titanium alloy ultrasonic probe into the melt, with a power of 600 - 900 W and an ultrasonic time of 5 - 10 min. After taking out the ultrasonic probe, let it stand for 2 - 3 min; 4) Then press the Mg ingot wrapped with aluminum foil into the aluminum melt with a bell jar and keep it for 2 - 3 min. After stirring evenly, heat up to 730 - 750 °C and press the refining agent into the aluminum melt with a bell jar and vibrate up and down for 2 - 3 min; 5) Insert the degassing gun, introduce high-purity argon gas for 20 - 30 min, then take out the degassing gun, heat up to 730 - 750 °C and keep it warm for 20 - 30 min, then cool down to 700 - 710 °C, skim the slag and then carry out casting. The mold used for casting is an iron mold; C. Atomization powder making Cut the middle part of the as-cast ingot obtained by pouring with a wire cutting machine, place it in a gas atomization powder making machine to prepare powder, sieve the prepared Al-Mg-Yb-Zr-TiB2 composite material powder, and select the fine powder passing through 200 meshes as the powder for additive manufacturing of Al-Mg-Yb-Zr-TiB2 composite material; D. Additive manufacturing The laser power of the additive manufacturing equipment is 200 - 450 W, the scanning speed is 300 - 1400 mm / s, the powder spreading thickness is 0.03 - 0.06 mm, and the scanning spacing is 0.05 - 0.15 mm. The forming substrate is made of Al-Mg-Yb-Zr alloy, the preheating temperature of the substrate is 80 - 150 °C, and the scanning strategy during additive manufacturing is layer-by-layer laser scanning.

8. Application of an Al-Mg-Yb-Zr-TiB2 composite material with light weight, high strength, high toughness and high modulus as described in any one of claims 1-5, characterized in that: The obtained Al-Mg-Yb-Zr-TiB2 composite material is used in at least one field of industrial machinery, transportation, and electronic packaging.

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