CN112760517A

CN112760517A - Graphite rotor for in-situ self-generated aluminum-based composite material

Info

Publication number: CN112760517A
Application number: CN202011571128.5A
Authority: CN
Inventors: 王浩伟; 王建中; 李爱平
Original assignee: Anhui Xiangbang Composite Material Co ltd; Anhui Huaibei Ceramic Aluminum New Material Research Institute Shanghai Jiaotong University
Current assignee: Anhui Xiangbang Composite Material Co ltd; Anhui Huaibei Ceramic Aluminum New Material Research Institute Shanghai Jiaotong University
Priority date: 2020-12-27
Filing date: 2020-12-27
Publication date: 2021-05-07
Anticipated expiration: 2040-12-27
Also published as: CN112760517B; DE202021100532U1

Abstract

The invention provides a graphite rotor for rotationally blowing argon in the preparation process of an in-situ authigenic aluminum-based composite material, which is provided with a rotating rod and a spray head, wherein the rotating rod comprises an inner pipe and an outer pipe, the outer pipe is connected with an argon blowing pipe through a rotary joint, the inner pipe is connected with a powder conveying bin, and the powder conveying bin is connected with a powder conveying air pipe.

Description

Graphite rotor for in-situ self-generated aluminum-based composite material

Technical Field

The invention relates to an aluminum matrix composite material, in particular to preparation of an in-situ authigenic aluminum matrix composite material.

Background

The in-situ self-generated aluminum-based composite material utilizes chemical reaction among different elements or chemicals under certain conditions to generate one or more ceramic phase particles in an aluminum matrix so as to achieve the purpose of improving the performance of a single metal alloy. The composite material prepared by in-situ self-generation has no pollution on the surface of the reinforcement body and good intermiscibility of the matrix and the reinforcement body. By selecting the reaction type and controlling the reaction parameters, different types and different quantities of in-situ reinforced particles can be obtained.

However, the in-situ autogenous aluminum-based composite material has high requirements on conditions including degassing and impurity removal in the preparation process, otherwise, the prepared composite material is easy to cause uneven particle size and distribution of the reinforcing phase, low mass fraction, or deteriorated structure, poor casting performance and reduced mechanical properties of the material.

In the prior art, the degassing treatment of the aluminum melt is carried out by adopting an inert gas rotary blowing technology. The core part of the technology is a hollow rotating rod with one end provided with a rotating nozzle, namely a rotor, when the technology is used, the rotor is inserted into an aluminum melt, inert gas is blown in through a middle pore passage of the rotating rod and is sprayed out by the rotating nozzle, formed bubbles are scattered into a large number of small bubbles due to high-speed rotation of the nozzle, hydrogen in the aluminum melt is attached to the small bubbles to be separated out into hydrogen, and meanwhile, impurity particles in the aluminum melt are adsorbed to float up to the liquid level, so that the purposes of degassing, removing impurities and purifying are achieved.

At present, most of aluminum melt degassing rotors are made of graphite materials, the graphite materials are excellent in thermal shock resistance and can be machined, aluminum liquid cannot infiltrate graphite, but the graphite materials have the defect that the graphite materials are not resistant to high temperature oxidation, so that the aluminum melt degassing rotors are required to be replaced after the service life is only 14-20 days.

It is therefore a problem addressed by those skilled in the art to effectively try to improve the reaction and preparation conditions to control the size, distribution, and settling segregation of the reinforcing phase and to increase the lifetime of argon-blown graphite rotors.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the technical problem to be solved by the present invention is how to improve the reaction and preparation conditions as much as possible to control the size, distribution and sedimentation segregation of the reinforcing phase and to increase the lifetime of the argon-blown graphite rotor.

In order to achieve the purpose, the invention provides a graphite rotor for rotationally blowing argon in the preparation process of an in-situ self-generated aluminum-based composite material, which is provided with a rotating rod and a spray head, wherein the rotating rod comprises an inner pipe and an outer pipe, the outer pipe is connected with an argon blowing pipe through a rotary joint, the inner pipe is connected with a powder conveying bin, and the powder conveying bin is connected with a powder conveying air pipe.

Further, the inner tube is made of a metal material and the outer tube is made of a graphite material.

Furthermore, alloy powder is arranged in the powder conveying bin.

Furthermore, the powder conveying gas pipe and the argon blowing gas pipe share the same argon gas source.

Furthermore, the powder conveying and feeding pipe is connected with a nitrogen gas source, and the argon gas blowing gas pipe is connected with an argon gas source.

Further, the inner wall of the inner pipe of the graphite rotor is provided with a wear-resistant coating.

According to the invention, the vacuum bag and the immersion pipe are used, the aluminum melt is sealed, a vacuum environment is generated by pumping, the oxygen and hydrogen partial pressure is reduced in the vacuum environment, and the degassing condition is enhanced. Meanwhile, the graphite rotating rod enters the aluminum melting furnace through the vacuum chamber, and is not in contact with oxygen in the whole process, so that the oxidation of the graphite rotor is prevented, and the service life of the graphite rotor is greatly prolonged.

According to the invention, a proper amount of metal magnesium is added into the composite material, so that the surface energy is reduced by adsorbing magnesium in aluminum liquid after particles are generated, and then the particles and aluminum form better combination, thus the magnesium is used as a means for reducing the surface energy of the particles and preventing agglomeration, and the phenomenon of particle sedimentation is effectively slowed down. Meanwhile, the viscosity of the aluminum liquid is increased due to the addition of magnesium, and according to a Stocks formula, the viscosity of the composite material is increased, the moving speed of particles is reduced, the particles cannot agglomerate due to mutual contact within a long time, and the particles are easily captured by alpha-Al crystal grains in the solidification process to form a uniform and stable reinforcement.

Usually in situGenerated TiB₂The particles are particles with the diameter of about 1 micron, and the particles with the size cannot be settled in the aluminum liquid. However, particles are often generated in a local region (at the interface between molten salt and molten aluminum), and are likely to agglomerate due to a high local concentration. And once the agglomeration is generated, the agglomeration is difficult to separate and refine, so that the segregation in the sedimentation and solidification processes occurs. The pulse magnetic field and the high-energy ultrasonic field are applied, the self protection of the reaction molten salt is utilized, the pulse magnetic field intensity is controlled to be 2-4T, and the high-energy ultrasonic field intensity is controlled to be 200-1800W/m². On one hand, the contact chance of molten salt and aluminum liquid can be increased, the reaction is accelerated, and the TiB generated in situ is enabled₂The particles are uniform and fine; on the other hand, the diffusion of particles from the high concentration region to the low concentration region of the reaction is promoted to ensure that the TiB₂The particles are uniform and dispersed, and further the sedimentation phenomenon of the composite material is relieved to a certain extent.

The invention realizes the synchronous conveying of argon gas rotary blowing and alloy raw materials through the specially designed graphite rotor, has high efficiency and compact structure, and can stir and distribute more uniformly when conveying the raw materials.

The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.

Drawings

FIG. 1 is a schematic illustration of a system for melt-controlled in-situ autogenous aluminum matrix composites with a vacuum bag in a preferred embodiment of the invention;

FIG. 2 is a schematic illustration of a system for melt-controlled in-situ autogenous aluminum matrix composites with electromagnetic stirring in a preferred embodiment of the invention;

FIG. 3 is a schematic illustration of a system for melt-controlled in-situ autogenous aluminum matrix composites with continuous processing in a preferred embodiment of the invention;

FIG. 4 is a schematic illustration of a system with powder injection of in situ autogenous aluminum matrix composites in a preferred embodiment of the invention;

FIG. 5 is a schematic view of the graphite rotor of FIG. 4;

FIG. 6 is a schematic illustration of a system for in situ autogenous aluminum matrix composites with permanent magnetic stirring in a preferred embodiment of the invention;

fig. 7 is a schematic view of the graphite rotor of fig. 6.

Detailed Description

The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.

Example one

As shown in figure 1, melting pure aluminum or aluminum alloy matrix at 700-760 ℃, placing an aluminum melting furnace 1 containing aluminum melt 2 on a hydraulic lifting table 10, and adding reaction salt and reaction auxiliary agent for reaction. The hydraulic lift 10 is raised so that the immersion tube 5 of the vacuum bag 3 disposed above the aluminum melting furnace 1 is immersed into the aluminum melt 2. The vacuum chamber 8 of the vacuum bag 3 is vacuumized through the pumping hole 4, so that the aluminum melt 2 enters the vacuum bag 3 under the action of atmospheric pressure.

And simultaneously carrying out argon rotary blowing on the aluminum melt: graphite rotor falls, graphite rotor's bull stick 6 is through setting up at the sealed bearing 7 at 3 tops of vacuum package, pass real empty room 8, insert shower nozzle 9 to the bottom of aluminium melt 2, the middle pore of argon gas through bull stick 6 blows in, spout by rotatory shower nozzle 9, the bubble of formation is broken up into a large amount of small bubbles because the high-speed rotation of shower nozzle 9, hydrogen in the aluminium melt 2 will depend on and separate out into hydrogen on these small bubbles, adsorb the impurity granule in the aluminium melt simultaneously and come up to the liquid level together, most bubbles get into in real empty room 8, then discharge through extraction opening 4. Through vacuum package 3 and dip tube 5, form sealedly with aluminium melt 2 self, the vacuum environment is produced in the air exhaust, and the vacuum environment reduces oxygen, hydrogen partial pressure, strengthens the degasification condition. Meanwhile, the graphite rotating rod 6 enters the aluminum melting furnace 1 through the vacuum chamber 8, and the whole process is free from oxygen, so that the oxidation of the graphite rotor is prevented, and the service life of the graphite rotor is greatly prolonged.

In a preferred embodiment of the present invention, the argon flow rate of the argon gas injection is set to 7 to 12L/min, and the stirring rotation speed is 270 to 320 r/min.

In a preferred embodiment of the present invention, the reaction salt comprises NaBF in a mass ratio of 1.2:1 to 1.8:1₄And Na₂TiF₆。

In a preferred embodiment of the present invention, the reaction promoter comprises Na in a mass ratio of 2.2:1:1 to 3.8:1:1₃AlF₆、LiF₃、LiCl₃。

In a preferred embodiment according to the invention, the above-mentioned reaction auxiliary is added in an amount of 8 to 12 wt% of the reaction salt.

In a preferred embodiment according to the invention, a pulsed magnetic field strength of 2-4T is applied during the reaction.

In a preferred embodiment according to the present invention, 200-1800W/m is applied during the reaction²High-energy ultrasound field strength.

In a preferred embodiment according to the invention, the reaction time is from 10min to 30 min.

Example two

As shown in fig. 2, melting a pure aluminum or aluminum alloy matrix at 700-760 ℃, placing an aluminum melt 2 in an aluminum melting furnace 1, and adding a reaction salt and a reaction auxiliary agent for reaction. The immersion pipe 5 of the vacuum bag 3 disposed above the aluminum melting furnace 1 is immersed into the aluminum melt 2. The vacuum chamber 8 of the vacuum bag 3 is vacuumized through the pumping hole 4, so that the aluminum melt 2 enters the vacuum bag 3 under the action of atmospheric pressure.

An electromagnetic stirring device is arranged below the aluminum melting furnace and comprises an inductor 12 and a frequency converter 11, and the electromagnetic stirring device is used for enabling the aluminum melt to generate stirring motion under the action of electromagnetic force.

EXAMPLE III

As shown in fig. 3, melting a pure aluminum or aluminum alloy matrix at 700-760 ℃, placing an aluminum melt 2 in an aluminum melting furnace 1, and adding a reaction salt and a reaction auxiliary agent for reaction. The immersion pipe 5 of the vacuum bag 3 disposed above the aluminum melting furnace 1 is immersed into the aluminum melt 2. The vacuum chamber 8 of the vacuum bag 3 is vacuumized through the pumping hole 4, so that the aluminum melt 2 enters the vacuum bag 3 under the action of atmospheric pressure.

An outlet flow passage 13 is arranged on the side wall of the upper part of the aluminum smelting furnace 1, and a flow stopping sliding plate 131 is arranged on the outlet flow passage 13; an inlet flow passage 14 is provided in a bottom side plate of the aluminum melting furnace 1, and a flow stop slide plate 141 is provided in the inlet flow passage 14. After a furnace of aluminum melt is processed, the flow stopping sliding plates 131 and 141 on the aluminum melt outlet runner 13 and the aluminum melt inlet runner 14 are opened, new aluminum melt to be processed is introduced from the aluminum melt inlet runner 14 at the bottom of the melting furnace, the processed aluminum melt in the aluminum melting furnace flows out from the outlet runner 13, after the aluminum melt with set flow rate flows into the aluminum melting furnace 1, the flow stopping sliding plates 131 and 141 are closed, and the operation is carried out again, so that the continuous processing of the aluminum melt under the vacuum condition can be realized, one furnace is not required to be vacuumized once, and the process preparation time and the energy consumption are greatly saved.

Example four

As shown in FIG. 4, a pure aluminum or aluminum alloy substrate is melted at 700-760 ℃, an aluminum melting furnace 1 containing an aluminum melt 2 is placed on a hydraulic lifting table 10, and a reaction salt and a reaction auxiliary agent are added for reaction. The hydraulic lift 10 is raised so that the immersion tube 5 of the vacuum bag 3 disposed above the aluminum melting furnace 1 is immersed into the aluminum melt 2. The vacuum chamber 8 of the vacuum bag 3 is vacuumized through the pumping hole 4, so that the aluminum melt 2 enters the vacuum bag 3 under the action of atmospheric pressure.

As shown in fig. 5, the graphite rotating rod 6 includes an inner tube 65 and an outer tube 63, and an argon blowing pipe 64 is provided in the inner tube 65 and the outer tube 63. The outer pipe 63 is connected with an argon gas injection pipe 631 through a rotary joint 62, the inner pipe 65 is connected with a powder conveying bin 61, the powder conveying bin 61 is connected with a powder conveying pipe 611, and a powder conveying pipeline 66 is arranged in the inner pipe 65.

Argon gas is blown through the outer tube 63 by an argon gas blowing tube 631; the alloy powder 9 in the powder conveying bin 61 is blown into the aluminum melt 2 through the inner pipe 65 by the powder conveying pipe 611.

Preferably, the inner tube 63 is made of a metal material such as copper or steel, and the outer tube 63 is made of a graphite material. This is to improve the wear resistance of the inner tube 63 against the erosion of the high-pressure gas and the powder.

Preferably, powder delivery tube 611 and argon purge gas tube 631 share the same argon gas source.

At the rootAccording to a preferred embodiment of the present invention, 200-1800W/m is applied during the reaction²High-energy ultrasound field strength.

EXAMPLE five

As shown in fig. 6, melting a pure aluminum or aluminum alloy matrix at 700-760 ℃, placing an aluminum melt 2 in an aluminum melting furnace 1, and adding a reaction salt and a reaction auxiliary agent for reaction. The immersion pipe 5 of the vacuum bag 3 disposed above the aluminum melting furnace 1 is immersed into the aluminum melt 2. The vacuum chamber 8 of the vacuum bag 3 is vacuumized through the pumping hole 4, so that the aluminum melt 2 enters the vacuum bag 3 under the action of atmospheric pressure.

As shown in fig. 7, the graphite rotating rod 6 includes an inner tube 65 and an outer tube 63, and an argon blowing pipe 64 is provided in the inner tube 65 and the outer tube 63. The outer pipe 63 is connected with an argon gas injection pipe 631 through a rotary joint 62, the inner pipe 65 is connected with a powder conveying bin 61, the powder conveying bin 61 is connected with a powder conveying pipe 611, and a powder conveying pipeline 66 is arranged in the inner pipe 65.

As shown in fig. 6, a track 17 of the permanent magnetic stirring device is disposed below the aluminum melting furnace 1, a carrier 16 capable of moving on the track 17 is disposed on the track 17, and a motor 18, a transmission belt 19 and a permanent magnet device 15 are disposed on the track 17, when the permanent magnetic stirring device operates, the carrier 16 moves below the aluminum melting furnace 1, the motor 18 drives the permanent magnet device 15 to rotate through the transmission belt, and a magnetic force is generated by interaction between a magnetic field of the permanent magnet device 15 and the aluminum melt 2 to push the aluminum melt 2 to perform stirring movement.

In other embodiments, the aluminum melting furnace can be arranged on the lifting platform, a rotating platform is rotatably arranged on the lifting platform, the rotating platform can rotate relative to the lifting platform under the driving of a motor, the aluminum melting furnace is fixedly arranged on the rotating platform, and when argon gas injection is carried out on aluminum liquid in the aluminum melting furnace, the aluminum melting furnace rotates along with the rotating platform and simultaneously drives the aluminum liquid therein, particularly the aluminum liquid on the furnace wall side of the aluminum melting furnace to move, so that the defect that the part of the aluminum liquid is weaker in argon gas rotary injection action is overcome

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims

1. The utility model provides a graphite rotor that is arranged in rotatory jetting of normal position autogenous aluminum matrix composite preparation in-process argon gas, its characterized in that, graphite rotor has bull stick and shower nozzle, the bull stick include inner tube and outer tube, the outer tube pass through rotary joint and argon gas jetting pipe and link to each other, the inner tube link to each other with powder transport bin, powder transport bin and powder transport trachea link to each other.

2. The graphite rotor for in-situ autogenous aluminum matrix composite production according to claim 1, wherein the inner tube is made of metal material and the outer tube is made of graphite material.

3. The graphite rotor for argon gas rotary blowing in the preparation process of the in-situ autogenous aluminum matrix composite material of claim 2, wherein the powder conveying bin is filled with alloy powder.

4. The graphite rotor for argon rotational blowing in the preparation process of in-situ autogenous aluminum matrix composite as claimed in claim 3, wherein said powder delivery pipe and argon blowing gas pipe share the same argon gas source.

5. The graphite rotor for in-situ autogenous aluminum matrix composite production of claim 4, wherein said powder supply pipe is connected to a source of nitrogen gas and said argon gas injection pipe is connected to a source of argon gas.

6. The graphite rotor for rotationally blowing argon gas in the preparation process of the in-situ autogenous aluminum matrix composite as claimed in claim 5, wherein the inner wall of the inner tube of the graphite rotor is provided with a wear-resistant coating.