阅读说明：本技术 一种圆桶形多层复合材料铸件的制备方法 (Preparation method of cylindrical multilayer composite casting ) 是由 卢德宏 徐志凯 于 2020-04-23 设计创作，主要内容包括：本发明公开一种圆桶形多层复合材料铸件的制备方法,属于金属基复合材料制备技术领域。所述方法为将铝合金放入熔炼炉中熔炼为金属液,一部分保持液态,另一部分降温至半固态区间保温,并加入B<Sub>4</Sub>C陶瓷颗粒,搅拌使之均匀分散于半固态浆料中,再将铝合金液升温至高于熔点的温度,备用；离心铸造机模具预热,启动离心铸造机,浇入含有B<Sub>4</Sub>C陶瓷颗粒的铝合金液并使之成型,待其凝固完成但仍处于高温时,再浇入不含陶瓷颗粒的铝合金,成型凝固得到铸件。该铸件具有三层结构,其中外层、内层均为铝合金,中间层为复合材料,且中间层与内、外层界面的B<Sub>4</Sub>C呈梯度分布。本发明所述方法获得的金属基复合材料强度、塑性和弹性模量综合性能优异。(The invention discloses a preparation method of a barrel-shaped multilayer composite casting, and belongs to the technical field of metal matrix composite preparation. The method comprises the steps of putting aluminum alloy into a smelting furnace to be smelted into molten metal, keeping one part of the molten metal in a liquid state, cooling the other part of the molten metal to a semi-solid state region, preserving heat, and adding B 4 C, ceramic particles are stirred to be uniformly dispersed in the semi-solid slurry, and then the temperature of the aluminum alloy liquid is raised to be higher than the melting point for later use; preheating the mould of the centrifugal casting machine, starting the centrifugal casting machine, and pouring the mixture containing B 4 C ceramic particles, forming the same, and solidifying the sameAnd when the temperature is still high, pouring aluminum alloy without ceramic particles, and forming and solidifying to obtain the casting. The casting has a three-layer structure, wherein the outer layer and the inner layer are both made of aluminum alloy, the middle layer is made of composite material, and B is the interface between the middle layer and the inner layer and the outer layer 4 C is distributed in a gradient way. The metal matrix composite material obtained by the method has excellent comprehensive properties of strength, plasticity and elastic modulus.)

1. A preparation method of a barrel-shaped multilayer composite casting is characterized by comprising the following steps:

(1) putting the aluminum alloy into a smelting furnace for smeltingSmelting into molten metal, wherein one part of the molten metal is kept in a liquid state; cooling the other part to semi-solid state region, and adding B₄C, ceramic particles are stirred to be uniformly dispersed in the semi-solid slurry, and then the temperature of the aluminum alloy liquid is raised to be higher than the melting point for later use;

(2) brushing paint on the mould of centrifugal casting machine, preheating, starting centrifugal casting machine, and pouring₄C, forming the aluminum alloy liquid of the ceramic particles, pouring aluminum alloy without the ceramic particles when the aluminum alloy liquid is solidified and still at high temperature, and forming and solidifying the aluminum alloy liquid;

(3) and after the casting is cooled, taking the casting out of the centrifugal casting machine, and finishing the barrel-shaped composite casting.

2. A method of producing a cylindrical shaped multilayer composite casting according to claim 1, characterized in that: the aluminum alloy in the step (1) is 2 series aluminum alloy, 5 series aluminum alloy or 7 series aluminum alloy.

3. A method of producing a cylindrical shaped multilayer composite casting according to claim 1, characterized in that: b in step (1)₄The particle size of the C ceramic particles is 5-100 mu m.

4. A method of producing a cylindrical shaped multilayer composite casting according to claim 1, characterized in that: in step (1) B₄The volume content of the C ceramic particles is 10-50% of the total volume content of the semi-solid slurry.

5. A method of producing a cylindrical shaped multilayer composite casting according to claim 1, characterized in that: the smelting temperature of the metal in the step (1) is 50-100 ℃ above the liquidus.

6. A method of producing a cylindrical shaped multilayer composite casting according to claim 1, characterized in that: the centrifugal casting process in the step (2) is carried out at the rotating speed of 500-4000 r/min for 3-60 min.

7. A method of producing a cylindrical shaped multilayer composite casting according to claim 1, characterized in that: in the step (2), the preheating temperature of the centrifugal casting mould is 200-550 ℃.

Technical Field

The invention relates to a preparation method of a barrel-shaped multilayer composite casting, belonging to the technical field of metal matrix composite preparation.

Background

The specific strength and the specific modulus of the traditional alloy material reach the limit, and the performance requirement and the use requirement of the material required by the current advanced equipment cannot be further met. And the particle reinforced metal matrix composite is one of the most promising advanced materials in the 21 st century. The composite material has high specific strength, high specific rigidity, high specific modulus and good high-temperature performance, and the particle reinforced metal matrix composite material has the advantages of wear resistance, fatigue resistance, low thermal expansion coefficient and good heat conductivity. However, the conventional ceramic particle reinforced metal matrix composite material is increased along with the increase of the ceramic particles, and although the strength and the elastic modulus are increased, the plasticity and the toughness are greatly reduced, so that the popularization and the application of the ceramic particle reinforced metal matrix composite material are influenced.

The Chinese patent CN102527978A realizes the casting and forming of the double-layer engine cylinder sleeve with the radial outer layer of the cylinder sleeve made of light alloy material and the inner layer made of particle reinforced composite material by a method of combining double-pouring ladle pouring and traditional centrifugal casting. However, the inner composite layer still has the problem of high brittleness, and when the inner surface is subjected to a large load or strong impact and the like, the problems of crack initiation, rapid propagation and the like are easy to occur.

The cylinder sleeve substrate described in the Chinese patent CN101338704A is Al-Si alloy, and Mg is added when molten metal is melted to form primary crystal Si and Mg₂The Si mixed reinforced particles are formed by distributing the reinforced layer inwards and distributing the non-reinforced layer inwards through centrifugal casting, and the reinforced layer and the non-reinforced layer form metallurgical bonding. However, the composite material in the outer layer still has the problems of high brittleness, crack initiation and rapid propagation when the outer surface of the component is subjected to a large load or strong impact and the like.

Disclosure of Invention

Aiming at the problem of poor plastic toughness of the conventional ceramic particle reinforced metal composite material, the invention aims to provide a preparation method of a high-toughness high-modulus cylindrical multilayer composite material casting, which comprises the following specific steps:

(1) smelting aluminum alloy in a smelting furnace to obtain molten metal, maintaining one part in liquid state and the other part in semi-solid state, and adding B₄C ceramic particleAnd (4) stirring to uniformly disperse the aluminum alloy particles in the semi-solid slurry, and then heating the aluminum alloy liquid to a temperature higher than the melting point for later use.

(2) Brushing paint on the mould of centrifugal casting machine, preheating, starting centrifugal casting machine, and pouring₄C, forming the aluminum alloy liquid of the ceramic particles, pouring aluminum alloy without the ceramic particles when the aluminum alloy liquid is solidified and still at high temperature, and forming and solidifying the aluminum alloy liquid.

(3) And after the casting is cooled, taking the casting out of the centrifugal casting machine to obtain the barrel-shaped composite casting.

Preferably, the preparation method of the high-strength, high-toughness and high-modulus cylindrical multilayer composite casting is characterized by comprising the following steps of: the metal substrate in the step (1) is 2 series, 5 series or 7 series aluminum alloy.

Preferably, B in step (1) of the present invention₄The particle size of the C ceramic particles is 5-100 μm.

Preferably, the volume content of the ceramic particles in the step (1) is 10-50% of the total volume content of the semi-solid slurry.

Preferably, the smelting temperature of the metal in the step (1) is 50-100 ℃ above the liquidus.

Preferably, the centrifugal casting process in the step (2) is carried out at a rotating speed of 500-4000 r/min for 3-60 min.

Preferably, the preheating temperature of the centrifugal casting mold in the step (2) is 200-550 ℃.

The principle of the invention is as follows: the method of the invention utilizes B₄The density of the C ceramic is 2.4-2.5 g/cm³) Density (2.7 g/cm) of the aluminum alloy substrate³) Low content of B due to centrifugal force during centrifugal casting₄In an aluminum alloy liquid of C particles, B₄The C particles are inwardly biased and the aluminum matrix is outwardly biased to form a double layer structure of an outer aluminum alloy layer and an inner composite material layer, and the interface B of the two layers₄C is distributed in a gradient way; pouring pure aluminum alloy liquid when the solidification is finished but still at high temperature, forming inner layer aluminum alloy under the action of centrifugal force, remelting inner surface of the middle layer to form B₄Gradient distribution of C and metallurgical bonding with inner layer(ii) a So that the casting forms a three-layer structure, wherein the outer layer and the inner layer are both pure aluminum alloy, the middle layer is a composite material layer, and B is the interface between the middle layer and the inner layer and the outer layer₄C is distributed in a gradient way. Due to B₄C has a high strength (compressive strength 4.2GPa, elastic modulus 420GPa), so B₄The C particle reinforced aluminum alloy composite material intermediate layer has high strength and high elastic modulus (rigidity), and further enables the integral casting to have high strength and high rigidity. The outer layer and the inner layer of the pure aluminum alloy have excellent toughness, so that the middle layer is not easy to crack, and the whole casting cannot crack and lose efficacy when being subjected to large load or strong impact on the outer surface or the inner surface, so that the composite material casting has high strength, high toughness and high modulus.

The invention has the beneficial effects that:

(1) the barrel casting prepared by the method has a unique multilayer composite structure of outer-layer aluminum alloy, middle-layer composite material and inner-layer aluminum alloy, the interfaces of all layers are metallurgically bonded, and ceramic particles are distributed in a gradient manner. The unique structure can not only improve the strength and rigidity of the casting, but also ensure that the whole casting is not easy to crack and lose efficacy no matter on the outer surface or the inner surface when being subjected to large load or strong impact, thereby ensuring the plastic toughness of the composite material casting and achieving the effects of high strength, high toughness and high modulus.

(2) The preparation of the barrel-shaped multilayer composite casting also has the advantages of conventional centrifugal casting: under the action of centrifugal force, the ceramic particles and the matrix are tightly combined, the compactness is good, the casting defects are few, the surface quality of the casting is high, the process is simple, the efficiency is high, and the mechanical and automatic batch production is convenient to carry out, so that the ceramic particle and matrix composite material has a great application prospect.

Drawings

Fig. 1 is a schematic structural view of a cylindrical multi-layer composite material.

Detailed Description

The present invention is further described in detail with reference to the following specific examples, but the scope of the present invention is not limited to the above description.