阅读说明：本技术 一种超细晶材料的增材制造方法 (Additive manufacturing method of ultrafine crystal material ) 是由 李羿含 张清贵 徐建 李星彤 王亮 于 2020-10-06 设计创作，主要内容包括：本发明涉及一种超细晶材料的增材制造方法,1)原材料的准备：将铝镁合金粉末与碳化钨粉末以体积比3-4:1混合均匀后,真空干燥得到冷喷涂粉末；2)冷喷涂沉积成型：将冷喷涂粉末冷喷涂到基体或预先沉积体的表面,形成冷喷涂沉积体；冷喷涂的参数为：气体压力为0.6-0.8MPa,气体加热温度为350-380℃,送粉速度为12-16g/min,喷涂移动速度为10mm/s,喷涂距离为25mm；3)搅拌摩擦处理：搅拌摩擦机的搅拌头对冷喷涂沉积体进行搅拌摩擦处理,得到具有均匀超细晶结构的冷喷涂沉积体。本发明操作简单、温度低、沉积效率以及致密度高,能够实现复杂形状飞机用零部件的制备,适用于超细晶材料的工业化生产。制备的飞机用零部件具有均匀超细晶结构以及优异的力学性能。(The invention relates to an additive manufacturing method of an ultrafine crystal material, 1) preparation of raw materials: uniformly mixing aluminum magnesium alloy powder and tungsten carbide powder in a volume ratio of 3-4:1, and then carrying out vacuum drying to obtain cold spraying powder; 2) cold spraying deposition molding: cold spraying the cold spraying powder on the surface of the matrix or the pre-deposited body to form a cold spraying deposited body; the parameters of cold spraying were: the gas pressure is 0.6-0.8MPa, the gas heating temperature is 350-380 ℃, the powder feeding speed is 12-16g/min, the spraying moving speed is 10mm/s, and the spraying distance is 25 mm; 3) stirring and rubbing treatment: and (3) carrying out stirring friction treatment on the cold spraying sediment body by a stirring head of the stirring friction machine to obtain the cold spraying sediment body with a uniform superfine crystal structure. The method has the advantages of simple operation, low temperature, high deposition efficiency and high density, can realize the preparation of parts for the aircraft with complex shapes, and is suitable for the industrial production of ultrafine grained materials. The prepared aircraft part has a uniform superfine crystal structure and excellent mechanical properties.)

1. The additive manufacturing method of the superfine crystal material is characterized by comprising the following steps:

1) preparation of raw materials: uniformly mixing aluminum magnesium alloy powder and tungsten carbide powder in a volume ratio of 3-4:1, and then carrying out vacuum drying to obtain cold spraying powder;

2) cold spraying deposition molding: cold spraying the cold spraying powder on the surface of the matrix or the pre-deposited body to form a cold spraying deposited body; wherein the parameters of cold spraying are as follows: the gas pressure is 0.6-0.8MPa, the gas heating temperature is 350-380 ℃, the powder feeding speed is 12-16g/min, the spraying moving speed is 10mm/s, and the spraying distance is 25 mm;

3) stirring and rubbing treatment: and (3) carrying out stirring friction treatment on the cold spraying sediment body through a stirring head of a stirring friction machine to obtain the cold spraying sediment body with a uniform superfine crystal structure.

2. The additive manufacturing method according to claim 1, wherein in step 1), the average particle diameter of the aluminum magnesium alloy powder is 2 to 15 μm; the average particle diameter of the tungsten carbide powder is 3 to 5 μm.

3. The additive manufacturing method according to claim 1, wherein in step 1), the parameters of vacuum drying are: vacuum degree of 10^-1-10^-2Pa, the drying temperature is 80-100 ℃, and the drying time is 4-5 h.

4. The additive manufacturing method according to claim 1, wherein in the step 3), the parameters of the friction stir processing are: the rotating speed of the stirring head is 600-1500r/min, and the moving speed of the stirring head is 2-4 mm/s.

5. The additive manufacturing method according to claim 1, wherein in step 3), the average grain size of the cold spray deposit after the friction stir processing is 0.2-0.5 μ ι η.

6. The additive manufacturing method according to claim 1, further comprising step 4): and repeating the steps 2) and 3) until the cold spraying deposition body with the uniform superfine crystal structure and the required thickness and shape is obtained, and finishing the additive manufacturing of the superfine crystal material.

Technical Field

The invention belongs to the technical field of additive manufacturing, and particularly relates to an additive manufacturing method of an ultrafine crystal material.

Background

The ultra-fine grain material is a material with at least one dimension in a three-dimensional space dimension in a submicron order (d is more than 0.1 mu m and less than 1 mu m), and has excellent mechanical properties, particularly high toughness and high strength.

With the rapid development of modern industry and science, the metal material is required to have higher mechanical property while maintaining the original imaging quality. The functions can be realized by refining the common steel grains to prepare the ultra-fine grain metal material, thereby replacing expensive alloy materials. Under the background of current resource shortage and increasingly serious environmental pollution, the technology reduces the consumption of expensive metal, improves the utilization rate and performance of materials, optimizes the dimensional tolerance and form and position tolerance, and has important significance for the manufacturing industry of China, particularly the fields of aviation and aerospace.

The method for preparing the ultra-fine grained material generally comprises: large plastic deformation methods such as equal-diameter bending channel deformation (ECAP), accumulative rolling deformation (ARB), high-pressure torsion deformation (HPT) and the like. These methods can produce bulk ultra-fine grained metal materials with large dimensions, but have some disadvantages in industrial production. Among them, ECAP industrial production equipment is expensive, and extrusion dies are severely worn, which leads to high production cost, and is commonly used for production of profiles and bars. The ARB process is suitable for the production of plates, but the material crack phenomenon in the production process is difficult to solve, so that the product quality and the yield are reduced. The HPT process is suitable for producing and processing bars, but the structure and the performance of large-size workpieces are not uniform. Therefore, the prior art is only suitable for preparing the ultra-fine crystal block material with simple shape, and cannot prepare parts for the airplane with complex shape. For example, CN201310479359.7 discloses a method for preparing an ultrafine grained titanium matrix composite by deformation of a constant-diameter curved channel, which can obtain a titanium matrix bulk composite with an ultrafine grained structure and high strength and good plasticity after multi-pass equal-diameter angular extrusion deformation, but cannot realize preparation of aircraft parts with complex shapes. Therefore, there is a need for an additive manufacturing method of ultra-fine grained material to solve the technical problem that people are eagerly solved but have not yet succeeded: the additive manufacturing method of the ultra-fine grain material cannot realize the preparation of aircraft parts with complex shapes.

Disclosure of Invention

The invention provides an additive manufacturing method of an ultrafine crystal material, aiming at the technical problems in the prior art, and solving the problems that the existing preparation method of the ultrafine crystal material has some defects in industrial production, such as the preparation of parts for an aircraft with complex shapes can not be realized.

The technical scheme for solving the technical problems is as follows:

an additive manufacturing method of an ultra-fine grained material comprises the following steps:

1) preparation of raw materials: uniformly mixing aluminum magnesium alloy powder and tungsten carbide powder in a volume ratio of 3-4:1, and then carrying out vacuum drying to obtain cold spraying powder;

2) cold spraying deposition molding: cold spraying the cold spraying powder on the surface of the matrix or the pre-deposited body to form a cold spraying deposited body; wherein the parameters of cold spraying are as follows: the gas pressure is 0.6-0.8MPa, the gas heating temperature is 350-380 ℃, the powder feeding speed is 12-16g/min, the spraying moving speed is 10mm/s, and the spraying distance is 25 mm;

3) stirring and rubbing treatment: and (3) carrying out stirring friction treatment on the cold spraying sediment body through a stirring head of a stirring friction machine to obtain the cold spraying sediment body with a uniform superfine crystal structure.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, in the step 1), the average grain diameter of the aluminum magnesium alloy powder is 2-15 μm; the average particle diameter of the tungsten carbide powder is 3 to 5 μm.

Further, in the step 1), the parameters of vacuum drying are as follows: vacuum degree of 10^-1-10^-2Pa, drying temperatureThe drying time is 4-5h at 80-100 ℃.

Further, in the step 3), the parameters of the friction stir processing are as follows: the rotating speed of the stirring head is 600-1500r/min, and the moving speed of the stirring head is 2-4 mm/s.

Further, in the step 3), the average grain size of the cold spray deposit after the friction stir treatment is 0.2 to 0.5 μm.

Further, the additive manufacturing method further comprises step 4): and repeating the steps 2) and 3) until the cold spraying deposition body with the uniform superfine crystal structure and the required thickness and shape is obtained, and finishing the additive manufacturing of the superfine crystal material.

The invention has the beneficial effects that:

(1) the additive manufacturing method has the advantages of simplicity in operation, low temperature, high deposition efficiency, high density and the like.

(2) In the prepared cold spraying deposition body, tungsten carbide particles are uniformly distributed on the interface between the aluminum magnesium alloy particles.

(3) On one hand, the pinning effect of the tungsten carbide particles can enhance the bonding strength among the aluminum magnesium alloy particles, so that the mechanical property of the material is improved; on the other hand, in the subsequent stirring and rubbing treatment process, the tungsten carbide particles as the second hard phase can increase the plastic deformation degree of the aluminum magnesium alloy particles and play a role in refining the grains, so that a uniform ultrafine crystal structure is obtained.

(4) The invention adopts a cold spraying process, can realize the preparation of parts for the airplane with complex shapes, is suitable for the industrial production of ultrafine crystal materials, and solves the technical problem which is expected to be solved but is not successful all the time.

Detailed Description

The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

Tungsten carbide is a compound consisting of tungsten and carbon, is a black hexagonal crystal, has metallic luster, hardness similar to that of diamond, and has stable chemical properties. The melting point is 2870 ℃, the boiling point is 6000 ℃, and the water-insoluble material is insoluble. It can be used as superhard cutter material and wear-resistant material, and can be used for manufacturing cutting tools, wear-resistant parts, smelting crucibles of metals such as copper, cobalt, bismuth and the like, wear-resistant semiconductor films and the like.

The basic principle of the friction stir processing is that the strong stirring action of the stirring head causes the processed material to generate violent plastic deformation, mixing and crushing, and the densification, homogenization and refinement of the microstructure are realized. It can eliminate the defects of shrinkage porosity, shrinkage cavity and the like in the product, and can also refine crystal grains, thereby improving the material performance.

The invention designs an additive manufacturing method of an ultra-fine grain material, which comprises the following steps:

1) preparation of raw materials: uniformly mixing aluminum magnesium alloy powder and tungsten carbide powder in a volume ratio of 3-4:1, and then carrying out vacuum drying to obtain cold spraying powder; wherein the average grain diameter of the aluminum magnesium alloy powder is 2-15 μm; the average grain diameter of the tungsten carbide powder is 3-5 mu m; the parameters of vacuum drying were: vacuum degree of 10^-1-10^-2Pa, the drying temperature is 80-100 ℃, and the drying time is 4-5 h;

2) cold spraying deposition molding: cold spraying the cold spraying powder on the surface of the matrix or the pre-deposited body to form a cold spraying deposited body; wherein the parameters of cold spraying are as follows: the gas pressure is 0.6-0.8MPa, the gas heating temperature is 350-380 ℃, the powder feeding speed is 12-16g/min, the spraying moving speed is 10mm/s, and the spraying distance is 25 mm;

3) stirring and rubbing treatment: carrying out friction stir treatment on the cold spraying deposition body through a stirring head of a friction stir machine: the stirring head rotates at a high speed and is vertically pressed into the cold spraying sediment body for stirring, the rotating speed of the stirring head is 600-1500r/min, the moving speed of the stirring head is 2-4mm/s, and the cold spraying sediment body with a uniform superfine crystal structure is obtained, and the average grain size of the cold spraying sediment body is 0.2-0.5 mu m;

4) and repeating the steps 2) and 3) until the cold spraying deposition body with the uniform superfine crystal structure and the required thickness and shape is obtained, and finishing the additive manufacturing of the superfine crystal material.

The additive manufacturing method is made aiming at the problems that the existing preparation method of the ultrafine grain material has some defects in industrial production, such as the preparation of parts for an aircraft with complex shapes can not be realized, and the like. After research, the inventor finds that the cold spraying deposition body with uniform superfine crystal structure can be obtained by mixing the aluminum magnesium alloy powder and the tungsten carbide powder in a volume ratio of 3-4:1, drying the mixture in vacuum to be used as a cold spraying raw material, and carrying out stirring friction treatment on the deposition body after cold spraying deposition forming, thereby realizing the preparation of the aircraft parts with complicated shapes. After a large number of experiments, the inventor finds that the parameters of cold spraying are designed as follows: the gas pressure is 0.6-0.8MPa, the gas heating temperature is 350-380 ℃, the powder feeding speed is 12-16g/min, the spraying moving speed is 10mm/s, the spraying distance is 25mm, the deposition efficiency and the compactness are high, and the average grain size of the prepared cold spraying sediment body is 0.2-0.5 mu m. Based on the test results, the inventor designs an additive manufacturing method of the ultra-fine grained material. Therefore, the inventor designs the technical problem which is desired to be solved but is not successful all the time: the additive manufacturing method of the ultra-fine grain material cannot realize the preparation of aircraft parts with complex shapes.

In the step 2), the gas pressure of the cold spraying of the invention is 0.6-0.8MPa, and low-pressure cold spraying equipment with a model Dymet manufactured by OPSC (Russia) can be used. Compared with the requirement of high-pressure cold spraying of more than 15 atmospheric pressures, the low-pressure cold spraying equipment basically has no working condition requirement, and the noise is less than 60 decibels. It has no high temperature, no flame, no dangerous gas, no radiation and chemical waste, and may be operated alone, and has high safety and excellent directionality. The spray area can be smaller than that of high-pressure cold spray without using a die, i.e., its operability is better.

In the step 2), in the cold spraying process, the cold spraying powder is impacted at supersonic speed, and aluminum-magnesium alloy powder particles are subjected to severe plastic deformation deposition molding in a solid state; during the deposition process, tungsten carbide powder particles with higher hardness are embedded into the aluminum magnesium alloy deposition body, so that the cold spraying deposition body of the composite material is formed.

In addition, the cold spraying has the advantages of simple operation, good spraying compactness, convenient control of spraying area and thickness, good spraying effect, low spraying temperature, effective prevention of particle oxidation and grain growth in the spraying process and the like. The low-pressure cold spraying equipment is adopted, and the advantages of low noise, high safety, good operability and directionality and the like are achieved.

Example 1

An additive manufacturing method of an ultra-fine grained material comprises the following steps:

1) preparation of raw materials: uniformly mixing aluminum magnesium alloy powder and tungsten carbide powder in a volume ratio of 3.5:1, and then carrying out vacuum drying to obtain cold spraying powder; wherein the average grain diameter of the aluminum magnesium alloy powder is 2 μm; the average particle size of the tungsten carbide powder was 5 μm; the parameters of vacuum drying were: vacuum degree of 10^-2Pa, the drying temperature is 90 ℃, and the drying time is 4.5 h;

2) cold spraying deposition molding: cold spraying the cold spraying powder on the surface of the matrix or the pre-deposited body to form a cold spraying deposited body; wherein the parameters of cold spraying are as follows: the gas pressure is 0.6MPa, the gas heating temperature is 350 ℃, the gas is helium with the purity of more than 99.9 percent, the powder feeding speed is 14g/min, the spraying moving speed is 10mm/s, and the spraying distance is 25 mm;

3) stirring and rubbing treatment: carrying out friction stir treatment on the cold spraying deposition body through a stirring head of a friction stir machine: the stirring head rotates at a high speed and is vertically pressed into the cold spraying sediment body for stirring, the rotating speed of the stirring head is 600r/min, the moving speed of the stirring head is 2mm/s, and the cold spraying sediment body with a uniform superfine crystal structure is obtained, and the average grain size of the cold spraying sediment body is 0.2-0.4 mu m;

4) and repeating the steps 2) and 3) until the cold spraying deposition body with the uniform superfine crystal structure and the required thickness and shape is obtained, and finishing the additive manufacturing of the superfine crystal material.

Example 2

An additive manufacturing method of an ultra-fine grained material comprises the following steps:

1) preparation of raw materials: uniformly mixing aluminum magnesium alloy powder and tungsten carbide powder in a volume ratio of 3:1, and then carrying out vacuum drying to obtain cold spraying powder; wherein the average grain diameter of the aluminum magnesium alloy powder is 8 μm; the average particle size of the tungsten carbide powder was 4 μm; the parameters of vacuum drying were: vacuum degree of 10^-1Pa, dryingThe temperature is 100 ℃, and the drying time is 5 h;

2) cold spraying deposition molding: cold spraying the cold spraying powder on the surface of the matrix or the pre-deposited body to form a cold spraying deposited body; wherein the parameters of cold spraying are as follows: the gas pressure is 0.7MPa, the gas heating temperature is 380 ℃, the gas is compressed air, the powder feeding speed is 12g/min, the spraying moving speed is 10mm/s, and the spraying distance is 25 mm;

3) stirring and rubbing treatment: carrying out friction stir treatment on the cold spraying deposition body through a stirring head of a friction stir machine: the stirring head rotates at a high speed and is vertically pressed into the cold spraying sediment body for stirring, the rotating speed of the stirring head is 1100 r/min, the moving speed of the stirring head is 3mm/s, and the cold spraying sediment body with a uniform superfine crystal structure is obtained, and the average grain size of the cold spraying sediment body is 0.2-0.5 mu m;

4) and repeating the steps 2) and 3) until the cold spraying deposition body with the uniform superfine crystal structure and the required thickness and shape is obtained, and finishing the additive manufacturing of the superfine crystal material.

Example 3

An additive manufacturing method of an ultra-fine grained material comprises the following steps:

1) preparation of raw materials: uniformly mixing aluminum magnesium alloy powder and tungsten carbide powder in a volume ratio of 4:1, and then carrying out vacuum drying to obtain cold spraying powder; wherein the average grain diameter of the aluminum magnesium alloy powder is 15 mu m; the average particle size of the tungsten carbide powder was 3 μm; the parameters of vacuum drying were: vacuum degree of 10^-2Pa, the drying temperature is 80 ℃, and the drying time is 4 hours;

2) cold spraying deposition molding: cold spraying the cold spraying powder on the surface of the matrix or the pre-deposited body to form a cold spraying deposited body; wherein the parameters of cold spraying are as follows: the gas pressure is 0.8MPa, the gas heating temperature is 365 ℃, the gas is helium with the purity of more than 99.9 percent, the powder feeding speed is 16g/min, the spraying moving speed is 10mm/s, and the spraying distance is 25 mm;

3) stirring and rubbing treatment: carrying out friction stir treatment on the cold spraying deposition body through a stirring head of a friction stir machine: the stirring head rotates at a high speed and is vertically pressed into the cold spraying sediment body for stirring, the rotating speed of the stirring head is 1500r/min, the moving speed of the stirring head is 4mm/s, and the cold spraying sediment body with a uniform superfine crystal structure is obtained, and the average grain size of the cold spraying sediment body is 0.3-0.5 mu m;

4) and repeating the steps 2) and 3) until the cold spraying deposition body with the uniform superfine crystal structure and the required thickness and shape is obtained, and finishing the additive manufacturing of the superfine crystal material.

The additive manufacturing method has the advantages of simplicity in operation, low temperature, high deposition efficiency, high density and the like. In the prepared cold spraying deposition body, tungsten carbide particles are uniformly distributed on the interface between the aluminum magnesium alloy particles. On one hand, the pinning effect of the tungsten carbide particles can enhance the bonding strength among the aluminum magnesium alloy particles, so that the mechanical property of the material is improved; on the other hand, in the subsequent stirring and rubbing treatment process, the tungsten carbide particles as the second hard phase can increase the plastic deformation degree of the aluminum magnesium alloy particles and play a role in refining the grains, so that a uniform ultrafine crystal structure is obtained. The invention adopts the cold spraying process, can realize the preparation of the aircraft parts with complex shapes, and is suitable for the industrial production of superfine crystal materials.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.