阅读说明：本技术 一种铝基复合材料及其制备方法 (Aluminum-based composite material and preparation method thereof ) 是由 池海涛 冯永平 张建雷 黄祯荣 刘金霞 于 2021-08-16 设计创作，主要内容包括：本发明公开了一种铝基复合材料及其制备方法,涉及金属基复合材料技术领域,其原料按照体积百分比包括：15-25%碳化硼、3-5%石墨烯或六方氮化硼、70-82%铝合金；其制备方法包括以下步骤：球磨混粉、烧结、均匀化处理及热处理；其制备装置包括依次连接的一级球磨机、二级球磨机、冷压成型机、加热炉、热压成型机,一级球磨机与二级球磨机之间连接有粉料输送机,冷压成型机、加热炉、热压成型机之间采用运输线进行传送,本发明制备的铝基复合材料密度为2.5-2.6g/cm～(3),且复合材料中的碳化硼增强体为自然界第三硬的陶瓷颗粒,耐磨性优异；同时铝基复合材料具备自润滑特性,石墨烯和六方氮化硼均为层状结构,复合材料在工作状态下可以有效的在表面铺展形成自润滑膜。(The invention discloses an aluminum-based composite material and a preparation method thereof, relating to the technical field of metal-based composite materials: 15-25% of boron carbide, 3-5% of graphene or hexagonal boron nitride and 70-82% of aluminum alloy; the preparation method comprises the following steps: ball milling, powder mixing, sintering, homogenizing treatment and heat treatment; the preparation device comprises a first-stage ball mill, a second-stage ball mill, a cold-pressing forming machine, a heating furnace and a hot-pressing forming machine which are connected in sequence, wherein a powder conveyer is connected between the first-stage ball mill and the second-stage ball mill, the cold-pressing forming machine, the heating furnace and the hot-pressing forming machine are conveyed by adopting a conveying line, and the density of the aluminum-based composite material prepared by the invention is 2.5-2.6g/cm 3 The boron carbide reinforcement in the composite material is third hard ceramic particles in the nature, so that the wear resistance is excellent; meanwhile, the aluminum-based composite material has a self-lubricating property, the graphene and the hexagonal boron nitride are both of a layered structure, and the composite material can be effectively spread on the surface to form a self-lubricating film in a working state.)

1. The aluminum-based composite material is characterized by comprising the following raw materials in percentage by volume: 15-25% of boron carbide, 3-5% of graphene or hexagonal boron nitride and 70-82% of aluminum alloy;

the average particle size of the boron carbide is 3-8 μm, the average size of the graphene or hexagonal boron nitride is 100nm, and the aluminum alloy is an Al-Cu aluminum alloy.

2. The method for preparing an aluminum matrix composite material as claimed in claim 1, comprising the steps of:

(1) ball milling and powder mixing: firstly, performing primary ball milling on aluminum alloy powder and boron carbide powder by adopting a two-stage ball milling process, setting the rotating speed of a primary ball mill to be 250-350 r/min for 1-2 h, mixing the powder obtained by the primary ball milling with graphene or hexagonal boron nitride, and performing secondary ball milling, wherein the rotating speed of a secondary ball mill is set to be 100-150 r/min for 3-4 h;

(2) and (3) sintering: placing the powder obtained in the step (1) into a mold for cold pressing, then placing the mold into a heating furnace for heating and heat preservation, then carrying out hot pressing by using a press machine, cooling to room temperature after the hot pressing is finished, and demolding to obtain an ingot;

(3) homogenizing: heating the cast ingot obtained in the step (2) to 515-535 ℃, preserving heat for 12-18 h, cooling along with the furnace after the heat preservation is finished, controlling the cooling rate to be 5-10 ℃/min, cooling to be below 100 ℃, and then air-cooling to room temperature to obtain a composite material;

(4) and (3) heat treatment: and (4) preserving the temperature of the composite material obtained in the step (3) at 528-548 ℃ for 1-2 h, performing aging treatment after water quenching, wherein the aging temperature is 190-210 ℃, and the aging time is 6-8 h.

3. The method for preparing the aluminum-based composite material as claimed in claim 2, wherein the powder in the step (2) is placed in a mold and cold-pressed to a pressure of 20-30 MPa, and then the mold is placed in a heating furnace (4) and heated to a temperature of 560 ℃ and 600 ℃ for a holding time of 1-2 h.

4. The device for preparing the aluminum matrix composite material according to claim 1, which comprises a primary ball mill (1), a secondary ball mill (2), a cold press molding machine (3), a heating furnace (4) and a hot press molding machine (5) which are connected in sequence, wherein a powder conveyor (6) is connected between the primary ball mill (1) and the secondary ball mill (2), and the cold press molding machine (3), the heating furnace (4) and the hot press molding machine (5) are conveyed by a conveying line (7);

the primary ball mill (1) and the secondary ball mill (2) respectively comprise a support (101), a cylinder body (102), a feeder (103), a discharger (104) and a first driving motor (105), a pair of bearing frames (106) are fixed at the upper end of the support (101), the cylinder body (102) is rotatably installed between the pair of bearing frames (106), a large gear ring (107) is fixed on the outer wall of the cylinder body (102), and a small gear (108) is connected to the outer wall of the large gear ring (107) in a meshed mode; the output end of the first driving motor (105) is connected with a speed reducer (109) through a coupler, and the output end of the speed reducer (109) is fixed with the pinion (108) through a rotating shaft; the inner wall of the barrel (102) is divided into a coarse material chamber (111) and a fine material chamber (112) through a partition plate (110), grinding steel balls (113) are placed in the coarse material chamber (111) and the fine material chamber (112), a discharging grate plate (114) is installed on the inner wall of the fine material chamber (112), the feeder (103) is installed at the left end of the barrel (102), and the discharger (104) is installed at the right end of the barrel (102);

the cold-pressing forming machine (3) and the hot-pressing forming machine (5) respectively comprise a workbench (301), an electric cabinet (302), a forming die (303), guide pillars (304) and an electric cylinder (305), the guide pillars (304) are fixedly mounted at four corners of the upper end surface of the workbench (301), the forming die (303) is fixedly mounted on the outer walls of the lower half sections of the four guide pillars (304) together, a sliding seat (306) is slidably mounted on the outer walls of the upper half sections of the four guide pillars (304) together, a die head is fixed on the lower end surface of the sliding seat (306), the upper end surface of the sliding seat (306) is fixed with the telescopic end of the electric cylinder (305), and the electric cabinet (302) is mounted on the front side of the workbench (301);

the heating furnace (4) comprises a furnace platform (401), a linear tunnel type hearth (402), a combustion system (403), a smoke exhaust system (404) and a turnover mechanism (405), wherein the upper end of the furnace platform (401) is fixed with the linear tunnel type hearth (402), the smoke exhaust system (404) is installed at the top end of the linear tunnel type hearth (402), the turnover mechanism (405) is arranged inside the linear tunnel type hearth (402), the turnover mechanism (405) comprises a plurality of groups of rotating shafts (4051) and turnover frames (4052), the turnover frames (4052) are fixed on the outer wall of the rotating shaft (4051), the outer wall of the middle part of the rotating shaft (4051) is fixed with driven gears (4053), the bottom ends of the driven gears (4053) are jointly engaged with racks (4054), two ends of the racks (4054) are fixed with sliding rods (4055), and two sliding rods (4055) are respectively installed on the inner walls of a pair of sliding sleeves (4056), the outer wall of the slide bar (4055) that is located the right side is fixed with reset spring (4057), and its right-hand member is fixed with riser (4058), the right-hand member face butt joint of riser (4058) has cam (4059), cam (4059) is connected with the output shaft of second driving motor (4050).

5. The apparatus for preparing an aluminum matrix composite according to claim 4, wherein: powder conveyer (6) are including conveyer pipe (601), conveying motor (602) and spiral auger blade (603), conveying motor (602) install in the left side outer wall of conveyer pipe (601), spiral auger blade (603) set up in the inner wall of conveyer pipe (601), the output of conveying motor (602) with spiral auger blade (603) are fixed mutually.

6. The apparatus for preparing an aluminum matrix composite according to claim 5, wherein: the upper side wall of the conveying pipe (601) is provided with a feeding hole and is connected with a discharging hole of the first-stage ball mill (1).

7. The apparatus for preparing an aluminum matrix composite according to claim 4, wherein: the hot-press forming machine (5) further comprises an electric heating device (501), and the electric heating device (501) comprises an electric heating plate, a heater and a temperature sensing rod.

8. The apparatus for preparing an aluminum matrix composite according to claim 4, wherein: the heating furnace (4) is internally provided with a pair of conveying lines (7), and the turnover mechanism (405) is arranged between the pair of conveying lines (7).

9. The apparatus for preparing an aluminum matrix composite according to claim 8, wherein: the conveying line (7) comprises a driving wheel (701), a driven wheel (702) and a metal mesh belt (703), the metal mesh belt (703) is sleeved on the outer walls of the driving wheel (701) and the driven wheel (702) together, and the driving wheel (701) is driven by a transmission motor (704).

10. The apparatus for preparing an aluminum matrix composite according to claim 4, wherein: the turnover frame (4052) is L-shaped, and the inner transverse frame and the inner vertical frame are perpendicular to each other.

Technical Field

The invention relates to the technical field of metal matrix composite material manufacturing, in particular to an aluminum matrix composite material and a preparation method thereof.

Background

The aluminum-based composite material takes aluminum or aluminum alloy as a matrix, and is reinforced by the cooperation of the reinforcing phase and the matrix, so that the material has excellent comprehensive properties such as light weight, high strength, high rigidity and the like, and meets the requirements of parts with higher requirements on internal quality. However, due to the existence of the reinforcing phase in the aluminum-based composite material, the viscosity of the melt is increased, the fluidity of the melt is reduced, the fluidity and the formability of the melt are poor in the pouring process by adopting the conventional gravity pouring process, and the feeding channel of the casting is not smooth in the solidification process of the melt, so that the shrinkage porosity and the low density in the casting are easily caused. The aluminum-based composite material can be widely applied to the fields of aviation, aerospace, automobiles, war industry and the like, and is paid more and more attention, and research and application of the material are more and more.

The methods for preparing the aluminum-based composite material are various, and the matrix material can be simply classified into three types according to the state when the matrix material is compounded with the reinforcing particles. One is liquid casting method, the second is solid powder metallurgy method the third is spray codeposition method between liquid and solid. When the aluminum-based composite material is prepared by adopting a casting method, the defects of segregation of a reinforcing phase, harmful interface reaction between a matrix and the reinforcing phase, large structure, uneven components, easiness in gas and impurity suction and the like are easily generated, and the volume fraction of the reinforcing phase is low, so that the mechanical property of the material is reduced. The powder metallurgy method can well avoid some defects in the casting method, such as controllable volume fraction, fine structure, uniform components and the like, but the powder metallurgy process is complex, easy to pollute, small in material size, long in production period and low in production efficiency, so that the wide application of the powder metallurgy method is limited to a certain extent; however, a large number of defects are easily formed in the powder mixing process of the existing powder metallurgy method to influence the quality of the composite material, and meanwhile, the existing process has more complex operation flow and high cost.

Therefore, it is necessary to provide an aluminum matrix composite and a method for preparing the same to solve the above problems.

Disclosure of Invention

The invention aims to provide an aluminum-based composite material and a preparation method thereof, which aim to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: an aluminum matrix composite material comprises the following raw materials in percentage by volume: 15-25% of boron carbide, 3-5% of graphene or hexagonal boron nitride and 70-82% of aluminum alloy;

the average particle size of the boron carbide is 3-8 μm, the average size of the graphene or hexagonal boron nitride is 100nm, and the aluminum alloy is an Al-Cu aluminum alloy.

The preparation method of the aluminum matrix composite material comprises the following steps:

(1) ball milling and powder mixing: firstly, performing primary ball milling on aluminum alloy powder and boron carbide powder by adopting a two-stage ball milling process, setting the rotating speed of a primary ball mill to be 250-350 r/min for 1-2 h, mixing the powder obtained by the primary ball milling with graphene or hexagonal boron nitride, and performing secondary ball milling, wherein the rotating speed of a secondary ball mill is set to be 100-150 r/min for 3-4 h;

(2) and (3) sintering: placing the powder obtained in the step (1) into a mold for cold pressing, then placing the mold into a heating furnace for heating and heat preservation, then carrying out hot pressing by using a press machine, cooling to room temperature after the hot pressing is finished, and demolding to obtain an ingot;

(3) homogenizing: heating the cast ingot obtained in the step (2) to 515-535 ℃, preserving heat for 12-18 h, cooling along with the furnace after the heat preservation is finished, controlling the cooling rate to be 5-10 ℃/min, cooling to be below 100 ℃, and then air-cooling to room temperature to obtain a composite material;

(4) and (3) heat treatment: and (4) preserving the temperature of the composite material obtained in the step (3) at 528-548 ℃ for 1-2 h, performing aging treatment after water quenching, wherein the aging temperature is 190-210 ℃, and the aging time is 6-8 h.

As a further improvement of the scheme, in the step (2), the powder is placed in a mold and is subjected to cold pressing until the pressure is 20-30 MPa, then the mold is placed in a heating furnace and is heated until the temperature is 560-600 ℃, and the heat preservation time is 1-2 hours.

A preparation device of an aluminum matrix composite comprises a primary ball mill, a secondary ball mill, a cold-pressing forming machine, a heating furnace and a hot-pressing forming machine which are connected in sequence, wherein a powder conveyor is connected between the primary ball mill and the secondary ball mill, and the cold-pressing forming machine, the heating furnace and the hot-pressing forming machine are conveyed by adopting a conveying line;

the primary ball mill and the secondary ball mill respectively comprise a support, a cylinder, a feeder, a discharger and a first driving motor, a pair of bearing frames are fixed at the upper end of the support, the cylinder is rotatably installed between the pair of bearing frames, a large gear ring is fixed on the outer wall of the cylinder, and a small gear is connected to the outer wall of the large gear ring in a meshed mode; the output end of the first driving motor is connected with a speed reducer through a coupler, and the output end of the speed reducer is fixed with the pinion through a rotating shaft; the inner wall of the barrel is divided into a coarse material chamber and a fine material chamber through a partition plate, grinding steel balls are placed in the coarse material chamber and the fine material chamber, a discharging grate plate is installed on the inner wall of the fine material chamber, the feeder is installed at the left end of the barrel, and the discharger is installed at the right end of the barrel;

the cold-pressing forming machine and the hot-pressing forming machine respectively comprise a workbench, an electric cabinet, a forming die, guide pillars and an electric cylinder, the guide pillars are fixedly mounted at four corners of the upper end surface of the workbench, the forming die is fixedly mounted on the outer walls of the lower half sections of the four guide pillars together, a sliding seat is slidably mounted on the outer walls of the upper half sections of the four guide pillars together, a die head is fixed on the lower end surface of the sliding seat, the upper end surface of the sliding seat is fixed with the telescopic end of the electric cylinder, and the electric cabinet is mounted on the front side of the workbench;

the heating furnace comprises a furnace platform, a linear tunnel type hearth, a combustion system, a smoke exhaust system and a turnover mechanism, the linear tunnel type hearth is fixed at the upper end of the furnace platform, the smoke exhaust system is installed at the top end of the linear tunnel type hearth, the turning mechanism is arranged in the linear tunnel type hearth and comprises a plurality of groups of rotating shafts and turning frames, the turning frame is fixed on the outer wall of the rotating shaft, driven gears are fixed on the outer wall of the middle part of the rotating shaft, the bottom ends of a plurality of driven gears are jointly meshed and connected with racks, the two ends of the rack are both fixed with slide bars, the two slide bars are respectively arranged on the inner walls of the pair of slide sleeves in a sliding way, the outer wall of the slide bar on the right side is fixed with a return spring, and the right end of the lifting mechanism is fixed with a vertical plate, the right end face of the vertical plate is abutted with a cam, and the cam is connected with an output shaft of a second driving motor.

As a further improvement to the above scheme, the powder conveyor comprises a conveying pipe, a conveying motor and a spiral auger blade, wherein the conveying motor is installed on the outer wall of the left side of the conveying pipe, the spiral auger blade is arranged on the inner wall of the conveying pipe, and the output end of the conveying motor is fixed with the spiral auger blade.

As a further improvement to the above scheme, the upper side wall of the conveying pipe is provided with a feeding hole and is connected with a discharging hole of the primary ball mill.

As a further improvement to the above scheme, the hot press forming machine further comprises an electric heating device, and the electric heating device comprises an electric heating plate, a heater and a temperature sensing rod.

As a further improvement to the above scheme, a pair of the conveying lines is arranged inside the heating furnace, and the turnover mechanism is arranged between the pair of the conveying lines.

As a further improvement to the above scheme, the transport line includes a driving wheel, a driven wheel and a metal mesh belt, the metal mesh belt is sleeved on the outer walls of the driving wheel and the driven wheel together, and the driving wheel is driven by a transmission motor.

As a further improvement to the scheme, the turnover frame is L-shaped, and the inner transverse frame and the inner vertical frame of the turnover frame are perpendicular to each other.

The invention has the beneficial effects that:

1. the density of the aluminum-based composite material prepared by the invention is only 2.5-2.6g/cm³The boron carbide reinforcement is lower than aluminum alloy, and the boron carbide reinforcement in the composite material is third hard ceramic particles in the nature, so that the wear resistance is excellent; meanwhile, the aluminum-based composite material has a self-lubricating property, the graphene and the hexagonal boron nitride are both of a layered structure, the composite material can be effectively spread on the surface to form a self-lubricating film in a working state, when the reinforcement is the graphene, the composite material can be used in a vacuum environment, and when the reinforcement is the hexagonal boron nitride, the composite material can be used in an atmospheric environment.

2. The invention adopts a double-stage ball milling process to ensure the completeness of powder, and prevents a large amount of defects from being formed in the powder mixing process to influence the quality of the composite material; meanwhile, the equipment and the process have the advantages of simple operation flow, low cost and higher economical efficiency.

3. The heating furnace comprises a furnace platform, a linear tunnel type hearth, a combustion system, a smoke exhaust system and a turnover mechanism, wherein the turnover mechanism comprises a plurality of groups of rotating shafts and a turnover frame, driven gears are fixed on the outer walls of the middle parts of the rotating shafts, the bottom ends of the driven gears are jointly meshed and connected with racks, slide bars are fixed at the two ends of the racks respectively, the two slide bars are respectively and slidably mounted on the inner walls of a pair of sliding sleeves, a reset spring is fixed on the outer wall of the slide bar on the right side, a second driving motor can be started, a cam is fixed at the output end of the second driving motor and is abutted with a vertical plate, so that the rack can be driven to move back and forth left and right under the rotation of the cam and the retraction performance of the reset spring, the rack and the driven gears are meshed and connected, the rotating shafts and the turnover frame can be further driven to do clockwise and anticlockwise back and forth movement, when an aluminum-based composite material pressing block on a conveying line enters the opening of the turnover frame, the turnover frame rotates 90 degrees clockwise to turn over 90 degrees of the pressed blocks, so that the pressed blocks are more uniformly sintered, the performance of the prepared aluminum-based composite material is more uniform, the phenomenon of neglect of the aluminum-based composite material is avoided, and the thermal stress generated in the finished composite material is also avoided.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a process diagram of the preparation process of the aluminum matrix composite material of the present invention;

FIG. 2 is a schematic view of a first perspective three-dimensional structure of an apparatus for preparing an aluminum-based composite material according to the present invention;

FIG. 3 is a schematic perspective view of a second perspective view of the apparatus for preparing a composite material according to the present invention;

FIG. 4 is a schematic perspective view of a primary ball mill according to the present invention;

FIG. 5 is a schematic view of a partial cross-sectional structure of a one-stage ball mill according to the present invention;

FIG. 6 is a schematic perspective view of a cold press molding machine according to the present invention;

FIG. 7 is a schematic perspective view of a heating furnace according to the present invention;

FIG. 8 is a schematic view of the installation of the turnover mechanism and the transport line inside the heating furnace according to the present invention;

FIG. 9 is an enlarged view of a portion of FIG. 8;

FIG. 10 is a schematic perspective view of a hot press forming machine according to the present invention;

FIG. 11 is a partial sectional view showing the construction of the powder conveyor of the present invention.

In the drawings, the components represented by the respective reference numerals are listed below:

1-first-stage ball mill, 101-support, 102-barrel, 103-feeder, 104-discharger, 105-first driving motor, 106-bearing frame, 107-big gear ring, 108-small gear, 109-speed reducer, 110-bin separation plate, 111-coarse material chamber, 112-fine material chamber, 113-grinding steel ball, 114-discharging grate plate, 2-second-stage ball mill, 3-cold press forming machine, 301-workbench, 302-electric cabinet, 303-forming die, 304-guide column, 305-electric cylinder, 306-slide seat, 4-heating furnace, 401-furnace platform, 402-linear tunnel type hearth, 403-combustion system, 404-smoke discharge system, 405-turnover mechanism, 4051-rotating shaft, 4052-turnover frame, 4053-driven gear, 4054-rack, 4055-slide bar, 4056-slide sleeve, 4057-return spring, 4058-vertical plate, 4059-cam, 4050-second driving motor, 5-hot press forming machine, 501-electric heating device, 6-powder conveyor, 601-conveying pipe, 602-conveying motor, 603-spiral auger blade, 7-conveying line, 701-driving wheel, 702-driven wheel, 703-metal mesh belt and 704-conveying motor.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The present invention will be further described with reference to the following examples.

Example 1

An aluminum matrix composite material comprises the following raw materials in percentage by volume: 15% of boron carbide, 3% of graphene and 82% of aluminum alloy; wherein the average grain diameter of the boron carbide is 3 μm, the average size of the graphene is 100nm, and the aluminum alloy is Al-Cu aluminum alloy.

As shown in fig. 1, a method for preparing an aluminum matrix composite material includes the following steps:

(1) ball milling and powder mixing: firstly, performing primary ball milling on aluminum alloy powder and boron carbide powder at the rotating speed of 250r/min for 1h by adopting a two-stage ball milling process, mixing the powder obtained by the primary ball milling with graphene or hexagonal boron nitride, and performing secondary ball milling at the rotating speed of 100r/min for 3 h;

(2) and (3) sintering: placing the powder obtained in the step (1) in a mold for cold pressing, then placing the mold in a heating furnace for heating and heat preservation, then carrying out hot pressing by using a press, cooling to room temperature after the hot pressing is finished, and demolding to obtain an ingot, wherein the powder is placed in the mold for cold pressing until the pressure is 20MPa, then placing the mold in the heating furnace for heating until the temperature is 560 ℃, and the heat preservation time is 1 h;

(3) homogenizing: heating the ingot obtained in the step (2) to 515 ℃, preserving heat for 12h, cooling along with the furnace after the heat preservation is finished, controlling the cooling rate to be 5 ℃/min, cooling to below 100 ℃, and then air-cooling to room temperature to obtain a composite material;

(4) and (3) heat treatment: and (4) preserving the temperature of the composite material obtained in the step (3) at 528 ℃ for 1h, carrying out aging treatment after water quenching, wherein the aging temperature is 190 ℃ and the aging time is 6 h.

Example 2

An aluminum matrix composite material comprises the following raw materials in percentage by volume: 20% of boron carbide, 4% of graphene or hexagonal boron nitride and 76% of aluminum alloy; wherein the average grain diameter of the boron carbide is 5 μm, the average size of the graphene is 100nm, and the aluminum alloy is Al-Cu aluminum alloy.

As shown in fig. 1, a method for preparing an aluminum matrix composite material includes the following steps:

(1) ball milling and powder mixing: firstly, performing primary ball milling on aluminum alloy powder and boron carbide powder by adopting a two-stage ball milling process, setting the rotating speed of a primary ball mill to be 300r/min for 1.5h, mixing the powder obtained by the primary ball milling with graphene or hexagonal boron nitride, and performing secondary ball milling, setting the rotating speed of a secondary ball mill to be 130r/min for 3.5 h;

(2) and (3) sintering: placing the powder obtained in the step (1) in a mold for cold pressing, then placing the mold in a heating furnace for heating and heat preservation, then carrying out hot pressing by using a press, cooling to room temperature after the hot pressing is finished, and demolding to obtain an ingot, wherein the powder is placed in the mold for cold pressing until the pressure is 25MPa, then placing the mold in the heating furnace for heating until the temperature is 580 ℃, and the heat preservation time is 1.5 h;

(3) homogenizing: heating the ingot obtained in the step (2) to 520 ℃, preserving heat for 16h, cooling along with the furnace after the heat preservation is finished, controlling the cooling rate to be 7 ℃/min, cooling to below 100 ℃, and then air-cooling to room temperature to obtain a composite material;

(4) and (3) heat treatment: and (4) preserving the temperature of the composite material obtained in the step (3) at 538 ℃ for 1.5h, carrying out aging treatment after water quenching, wherein the aging temperature is 200 ℃ and the aging time is 7 h.

Example 3

An aluminum matrix composite material comprises the following raw materials in percentage by volume: 25% boron carbide, 5% hexagonal boron nitride, 70% aluminum alloy; wherein the average grain diameter of the boron carbide is 8 μm, the average size of the hexagonal boron nitride is 100nm, and the aluminum alloy is Al-Cu aluminum alloy.

As shown in fig. 1, a method for preparing an aluminum matrix composite material includes the following steps:

(1) ball milling and powder mixing: firstly, performing primary ball milling on aluminum alloy powder and boron carbide powder at the rotating speed of 350r/min for 2h by adopting a two-stage ball milling process, mixing the powder obtained by the primary ball milling with graphene or hexagonal boron nitride, and performing secondary ball milling at the rotating speed of 150r/min for 4 h;

(2) and (3) sintering: placing the powder obtained in the step (1) in a mold for cold pressing, then placing the mold in a heating furnace for heating and heat preservation, then carrying out hot pressing by using a press, cooling to room temperature after the hot pressing is finished, and demolding to obtain an ingot, wherein the powder is placed in the mold for cold pressing until the pressure is 30MPa, then placing the mold in the heating furnace for heating until the temperature is 600 ℃, and the heat preservation time is 2 hours;

(3) homogenizing: heating the cast ingot obtained in the step (2) to 535 ℃, preserving heat for 18h, cooling along with the furnace after the heat preservation is finished, controlling the cooling rate to be 10 ℃/min, cooling to below 100 ℃, and then air-cooling to room temperature to obtain a composite material;

(4) and (3) heat treatment: and (4) preserving the temperature of the composite material obtained in the step (3) at 548 ℃ for 2h, carrying out aging treatment after water quenching, wherein the aging temperature is 210 ℃ and the aging time is 8 h.

Example 4

On the basis of the embodiment 1, 2 or 3, the device for preparing the aluminum matrix composite comprises a primary ball mill 1, a secondary ball mill 2, a cold press molding machine 3, a heating furnace 4 and a hot press molding machine 5 which are connected in sequence, wherein a powder conveyer 6 is connected between the primary ball mill 1 and the secondary ball mill 2, and the cold press molding machine 3, the heating furnace 4 and the hot press molding machine 5 are conveyed by a conveying line 7;

as shown in fig. 2, 4 and 5, each of the primary ball mill 1 and the secondary ball mill 2 includes a support 101, a cylinder 102, a feeder 103, a discharger 104 and a first driving motor 105, a pair of bearing frames 106 are fixed at the upper end of the support 101, the cylinder 102 is rotatably installed between the pair of bearing frames 106, a bull gear 107 is fixed on the outer wall of the cylinder 102, and a pinion 108 is connected to the outer wall of the bull gear 107 in a meshing manner; the output end of the first driving motor 105 is connected with a speed reducer 109 through a coupling, and the output end of the speed reducer 109 is fixed with a pinion 108 through a rotating shaft; the inner wall of the cylinder body 102 is divided into a coarse material chamber 111 and a fine material chamber 112 by a partition plate 110, grinding steel balls 113 are placed in the coarse material chamber 111 and the fine material chamber 112, a discharging grate plate 114 is installed on the inner wall of the fine material chamber 112, a feeder 103 is installed at the left end of the cylinder body 102, and a discharger 104 is installed at the right end of the cylinder body 102;

as shown in fig. 2 and 6, each of the cold press molding machine 3 and the hot press molding machine 5 includes a workbench 301, an electric cabinet 302, a molding die 303, guide pillars 304 and an electric cylinder 305, the guide pillars 304 are fixedly mounted at four corners of the upper end surface of the workbench 301, the molding die 303 is fixedly mounted on the outer walls of the lower half sections of the four guide pillars 304, a sliding seat 306 is slidably mounted on the outer walls of the upper half sections of the four guide pillars 304, a die head is fixed on the lower end surface of the sliding seat 306, the upper end surface of the sliding seat 306 is fixed with the telescopic end of the electric cylinder 305, and the electric cabinet 302 is mounted on the front side of the workbench 301;

as shown in fig. 2, 7, 8 and 9, the heating furnace 4 includes a furnace platform 401, a linear tunnel type hearth 402, a combustion system 403, a smoke exhaust system 404 and a turnover mechanism 405, the upper end of the furnace platform 401 is fixed with the linear tunnel type hearth 402, the top end of the linear tunnel type hearth 402 is provided with the smoke exhaust system 404, the interior of the linear tunnel type hearth 402 is provided with the turnover mechanism 405, the turnover mechanism 405 includes a plurality of sets of rotating shafts 4051 and turnover frames 4052, the turnover frames 4052 are L-shaped, and the internal cross frames and vertical frames are perpendicular to each other, the turnover frames 4052 are fixed on the outer wall of the rotating shafts 4051, the outer wall of the middle part of the rotating shafts 4051 is fixed with driven gears 4053, the bottom ends of the driven gears 4053 are jointly engaged with racks 4054, the two ends of the racks 4054 are fixed with slide bars 4055, the two slide bars 4055 are respectively slidably mounted on the inner walls of a pair of slide sleeves 4056, the outer wall of the slide bar 4055 on the right side is fixed with a return spring 4057, a vertical plate 4058 is fixed at the right end of the driving shaft, a cam 4059 is abutted against the right end face of the vertical plate 4058, and the cam 4059 is connected with an output shaft of a second driving motor 4050; the heating furnace 4 is provided with a pair of transport lines 7 inside, and the turnover mechanism 405 is provided between the pair of transport lines 7.

As shown in fig. 2 and 10, the hot press forming machine 5 further includes an electric heating device 501, and the electric heating device 501 includes an electric heating plate, a heater, and a temperature sensing rod.

As shown in fig. 2 and 8, the flour conveyor 6 includes a conveying pipe 601, a conveying motor 602 and a spiral auger blade 603, the conveying motor 602 is installed on the outer wall of the left side of the conveying pipe 601, the spiral auger blade 603 is arranged on the inner wall of the conveying pipe 601, and the output end of the conveying motor 602 is fixed with the spiral auger blade 603; the upper side wall of the conveying pipe 601 is provided with a feeding hole and is connected with a discharging hole of the first-stage ball mill 1.

As shown in fig. 2 and 11, the transport line 7 includes a driving wheel 701, a driven wheel 702, and a metal mesh belt 703, the metal mesh belt 703 is sleeved on the outer walls of the driving wheel 701 and the driven wheel 702, and the driving wheel 701 is driven by a transmission motor 704.

The working principle of the embodiment 4 is as follows: firstly, materials enter the barrel 102 of the first-stage ball mill 1 and the second-stage ball mill 2 from the feeder 103, after the first driving motor 105 of the first-stage ball mill 1 and the second-stage ball mill 2 are started simultaneously, the pinion 108 can be driven to rotate at a low speed under the speed reduction action of the speed reducer 109, the pinion 108 and the bull gear 107 are in meshed connection, the bull gear 107 and the barrel 102 can be further driven to start rotating, the inner wall of the barrel 102 is divided into a coarse material chamber 111 and a fine material chamber 112 through a partition plate 110, grinding steel balls 113 are respectively arranged in the coarse material chamber 111 and the fine material chamber 112, the grinding steel balls 113 are in inertia, centrifugal force and friction force action with the inner wall of the barrel 102, when the grinding steel balls are attached to the inner wall by the barrel at a certain height, the grinding steel balls are thrown off due to the gravity action of the grinding steel balls 113, the falling grinding steel balls 113 crush the materials in the barrel like a projectile body, and after the coarse material chamber 111 achieves coarse grinding, the materials enter a fine material chamber 112 through a single-layer partition plate 110, grinding steel balls 113 are also arranged in the chamber, the materials are further ground, and the powdery materials are discharged through a discharging grate plate 114, so that the grinding operation is completed; then, the powdery material is conveyed into a forming die 303 of the cold-pressing forming machine 3 through a conveying line 7, and then the electric control box 302 controls a telescopic rod of the electric cylinder 305 to extend downwards, so that the sliding base 306 can be driven to move downwards along the outer walls of the four guide pillars 304, a die head is fixed on the lower end surface of the sliding base 306, and when the die head enters the forming die 303, the powdery material can be extruded into blocks; then after the block-shaped material is demoulded, the block-shaped material is conveyed into the heating furnace 4 through the conveying line 7 again for heating and heat preservation, the second driving motor 4050 can be started in the heating and heat preservation processes, the output end of the second driving motor 4050 is fixedly provided with the cam 4059, the cam 4059 is abutted with the vertical plate 4058, and then the rack 4054 can be driven to move back and forth left and right under the rotation of the cam 4059 and the retraction performance of the return spring 4057, because the rack 4054 is in meshed connection with the driven gear 4053, the rotating shaft 4051 and the turning frame 4052 can be further driven to do clockwise and anticlockwise back and forth movement, when the aluminum-based composite material pressing block on the conveying line 7 enters the opening of the turning frame 4052, the turning frame 4052 rotates clockwise 90 degrees to turn over the pressing block 90 degrees, so that the sintering of the pressing block is more uniform, the performance of the prepared aluminum-based composite material is more uniform, and the phenomenon of poor phenomenon can not occur, and the thermal stress generated in the finished composite material is avoided, and finally, the hot pressing is carried out by using a hot pressing forming machine 5, and the final aluminum-based composite material can be obtained after cooling to room temperature and demoulding after the hot pressing is finished.

In the comprehensive examples 1-4, the density of the aluminum matrix composite material prepared by the invention is only 2.5-2.6g/cm³Lower than aluminum alloy, and the boron carbide reinforcement in the composite material is the third hard ceramic in natureThe particles are excellent in wear resistance; meanwhile, the aluminum-based composite material has a self-lubricating property, the graphene and the hexagonal boron nitride are both of a layered structure, the composite material can be effectively spread on the surface to form a self-lubricating film in a working state, in addition, when the reinforcement is the graphene, the composite material can be used in a vacuum environment, and when the reinforcement is the hexagonal boron nitride, the composite material can be used in an atmospheric environment; a double-stage ball milling process is adopted to ensure the completeness of the powder, so that the influence on the quality of the composite material caused by a large number of defects formed in the powder mixing process is prevented; meanwhile, the equipment and the process have the advantages of simple operation flow, low cost and higher economy.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.