CN103276389B - Aluminium oxide strengthens aluminum-based in-situ composite materials and preparation method thereof with zirconium diboride - Google Patents

Abstract

The invention relates to an alumina and zirconium diboride reinforced aluminum-based in-situ composite material and a preparation method thereof. ZrO ₂ particles and B or B ₂ O ₃ particles are mixed and ball-milled, and the mixed particles are added into a matrix after ball milling, and the matrix is The particle filling area is subjected to friction stir processing, the rotation speed of the stirring tool is 600-3000r/min, the travel speed is 30-60mm/min, the pressing amount is 0.05-0.6mm, the inclination angle is 0-3°, and the processing times are 3 ~8 times, the ZrO ₂ , B or B ₂ O ₃ particles react with the aluminum matrix during the processing, and finally obtain the alumina and zirconium diboride reinforced aluminum matrix in-situ composite material. In the aluminum-based composite material prepared by the present invention, the in-situ synthesized particles Al ₂ O ₃ and ZrB ₂ both have extremely high hardness and thermal stability, so that this type of composite material has higher high temperature wear resistance.

Description

Alumina and zirconium diboride reinforced aluminum matrix in-situ composite material and preparation method thereof

technical field

The invention relates to the field of preparation methods of aluminum-based composite materials, in particular to a method for in-situ synthesis of (Al ₂ O ₃ +ZrB ₂ ) particle-reinforced aluminum-based composite materials through friction stir processing.

Background technique

Aluminum matrix composites have the advantages of high specific strength, high specific modulus, high thermal conductivity, low thermal expansion coefficient, high temperature resistance, wear resistance, etc., and occupy an important position in aerospace, automobile and other manufacturing fields. Compared with fiber-reinforced aluminum-matrix composites, particle-reinforced aluminum-matrix composites have the advantages of isotropy, relatively simple preparation, and relatively low cost, and are currently the focus of research in the field of metal matrix composites.

At present, the preparation of particle-reinforced aluminum matrix composites mainly includes five processing techniques: liquid state, solid state, semi-solid state, deposition and in-situ synthesis. Compared with several other processes, the preparation of particle-reinforced gold-aluminum matrix composites by in-situ synthesis method has the following advantages: (1) The thermodynamic properties of the in-situ-generated reinforcement are stable; (2) The interface between the reinforcement and the matrix is pollution-free and has high bonding strength ; (3) The reinforcement is fine and uniformly distributed in the matrix; (4) The size of the reinforcement is not limited by the size of the initially added particles.

After searching the literature of the prior art, it was found that "Microstructure and high temperature wear of aluminum matrix composites fabricated by reaction from Al-ZrO ₂ " published in "Powder Technology" (2012, Vol. -B elemental powders”, which proposed to synthesize (Al ₂ O ₃ +ZrB ₂ ) particle-reinforced aluminum matrix composites by exothermic dispersion reaction (XD). The specific method is: use Al powder, B powder and ZrO ₂ powder as As raw materials, ball milling, briquetting, and heating in a vacuum furnace to generate Al ₂ O ₃ and ZrB ₂ particles. Studies have shown that this type of composite material has high temperature and wear resistance. The disadvantages are: the synthetic particles are in the micron scale, the particles are relatively coarse, and the reaction needs to be carried out under vacuum and high temperature (800°C), resulting in high production costs.

Friction stir processing technology is a solid-state processing method developed on the basis of friction stir welding technology. The preparation of particle-reinforced aluminum matrix composites by this technology has the following unique advantages: (1) During the processing, the composite material undergoes dynamic recrystallization to form fine equiaxed grains, and its mechanical properties are significantly improved; (2) The processing process is easy to achieve precise control; (3) The depth of the composite material can be freely selected by changing the length of the stirring tool; (4) The amount of particle reinforcement phase in the composite material can be freely adjusted by changing the size and spacing of blind holes or grooves; (5) The process does not produce Harmful gas is a green and energy-saving process with no radiation and less noise.

Friction stir processing in situ synthesis technology is a composite preparation process based on friction stir processing technology and in situ synthesis technology. Disperse the desired reinforcing particles. This technology combines the advantages of friction stir processing technology and in situ synthesis technology.

Chinese patent CN102021557A discloses an Al ₂ O ₃ +TiB ₂ composite coating on the surface of an aluminum alloy and its preparation method. First, a number of grooves with a depth of 0.5 mm to 2 mm and a width of 0.5 mm to 2 mm are opened on the surface of the aluminum alloy. , fill the ball-milled mixed powder containing 30% to 70% TiO ₂ and 30% to 70% B ₂ O ₃ in the groove, and then through friction stir processing, so that the mixed powder of TiO ₂ and B ₂ O ₃ is evenly distributed on the aluminum In the surface layer of the alloy, the surface layer is finally heated by induction to produce a chemical reaction 3TiO ₂ +3B ₂ O ₃ +10Al=3TiB ₂ +5Al ₂ O ₃ to obtain an Al ₂ O ₃ +TiB ₂ composite coating. A metallurgical bonding interface is formed between the layer and the substrate. In this patent, the chemical reaction occurs after the friction stir processing, and its disadvantages are: after the friction stir processing, a subsequent induction heating process is required for the chemical reaction to occur, the process steps are complicated, and the contact between TiO ₂ and B ₂ O ₃ particles is insufficient during the induction heating process , which is not conducive to complete reaction.

Contents of the invention

The object of the present invention is to provide an alumina and zirconium diboride reinforced aluminum-based in-situ composite material and a preparation method thereof.

The technical scheme adopted by the present invention is:

A method for preparing aluminum oxide and zirconium diboride reinforced aluminum-based in-situ composite materials, comprising the following steps:

( ₁ ) Mix ZrO2 particles with B particles at a mass ratio of 11: ₂ , or mix ZrO2 particles with B2O3 particles at a mass ratio of ₅ : ₂ , and ball mill the mixed particles;

(2) Use pure aluminum or aluminum alloy plate as the matrix, and add the mixed particles into the matrix after ball milling;

(3) Perform friction stir processing on the particle-filled area of the matrix, the rotation speed of the stirring tool is 600-3000r/min, the travel speed is 30-60mm/min, the pressing amount is 0.05-0.6mm, and the inclination angle is 0-3° , the processing times are 3 to 8 times. During the processing, the ZrO ₂ , B or B ₂ O ₃ particles and the aluminum matrix undergo a chemical reaction together, and finally the alumina and zirconium diboride reinforced aluminum matrix in-situ composite material is obtained.

The ball milling time in the above step (1) is 1-10 hours, the rotation speed is 50-100 r/min, and the ball-to-material ratio is 5-15:1.

The average particle size of ZrO ₂ particles is between 10nm and 10μm, and the purity is 90% to 99.9%. The average particle size of B or B ₂ O ₃ particles is between 10nm and 100μm, and the purity is 90% to 99.9%.

The method of adding the mixed particles described in the above step (2) into the matrix includes: (1) opening grooves or blind holes on the surface or inside of the matrix, adding the mixed particles into the grooves or blind holes, and filling them; (2) The mixed particles are added to the surface of the substrate by spraying or coating.

The processing direction or rotation direction of the two times before and after the processing in the above step (3) is the same or opposite.

The above chemical reaction products are Al ₂ O ₃ and ZrB ₂ particles, and the chemical reaction equation is: 4Al+3ZrO ₂ +6B→2Al ₂ O ₃ +3ZrB ₂ or 10Al+3ZrO ₂ +3B ₂ O ₃ →5Al ₂ O ₃ + 2ZrB ₂ . The aluminum oxide and zirconium diboride reinforced aluminum-based in-situ composite material prepared by the above method.

Compared with the prior art solutions, the above-mentioned technical solution of the present invention has the following advantages: in the preparation of aluminum-based composite materials by using the present invention, the in _- situ synthesized particles _Al2O3 and _ZrB2 have extremely high hardness and thermal stability, so that This type of composite material has high temperature and wear resistance. Compared with the patent CN102021557A, the present invention takes place in the friction stir processing process without the need for subsequent heating process, saving production cost, and in the friction stir processing process, the ZrO ₂ , B and Al substrates react fully under the action of vigorous stirring.

Description of drawings

Fig. 1 is a schematic diagram of the working principle of friction stir processing of the preparation method of the present invention;

Fig. 2 is the product appearance figure that the present invention makes;

Among them, 1. Aluminum plate, 2. Stirring tool, 3. Particle filling area, 4. Aluminum matrix composite material area.

detailed description

Below in conjunction with embodiment further illustrate.

Example 1

Base material: 10mm thick 6061 aluminum alloy plate.

Added particles: monoclinic zirconia (average particle size 80nm, purity 99.8%), amorphous boron (average particle size 500nm, purity 96%).

ZrO ₂ particles and B particles were mixed at a mass ratio of 11:2, and the mixed particles were ball milled; the ball milling time was 2 hours, the speed was 80r/min, and the ball-to-material ratio was 15:1.

Three rows of blind holes are processed in the middle area of the aluminum plate, the hole depth and diameter are both 4mm, and the hole spacing is 2mm.

After ball milling, the mixed particles are poured into the volatile organic solvent, mixed evenly and then added into the blind hole or groove; after the organic solvent volatilizes, fill again until it is filled;

Friction stir processing in-situ synthesis process parameters: rotation speed 900r/min, travel speed 60mm/min, press amount 0.1mm, inclination angle 2.5°, processing times 5 times, all 5 times along the same travel direction.

The microhardness of the obtained material composite layer is about 2.5 times that of the base material, and the high temperature wear resistance is 1.4 times that of the base material.

Example 2

Base material: 10mm thick 6061 aluminum alloy plate.

Added particles: monoclinic zirconia (average particle size 80nm, purity 99.8%), amorphous boron (average particle size 500nm, purity 96%).

ZrO ₂ particles and B particles were mixed at a mass ratio of 11:2, and the mixed particles were ball milled; the ball milling time was 3 hours, the speed was 60r/min, and the ball-to-material ratio was 15:1.

Three rows of blind holes are processed in the middle area of the aluminum plate, the hole depth and diameter are both 4mm, and the hole spacing is 2mm.

After ball milling, the mixed particles are poured into the volatile organic solvent, mixed evenly and then added into the blind hole or groove; after the organic solvent volatilizes, fill again until it is filled;

Friction stir processing in-situ synthesis process parameters: rotation speed 1100r/min, travel speed 50mm/min, press amount 0.2mm, inclination angle 2°, processing times 6 times, all 6 times along the same travel direction.

The microhardness of the obtained material composite layer is about 2.3 times that of the base material, and the high temperature wear resistance is 1.6 times that of the base material.

Example 3

Base material: 10mm thick aluminum plate.

Added particles: monoclinic zirconia (average particle size 80nm, purity 99.8%), amorphous boron (average particle size 500nm, purity 96%).

ZrO ₂ particles and B particles were mixed at a mass ratio of 11:2, and the mixed particles were ball milled; the ball milling time was 8 hours, the speed was 40r/min, and the ball-to-material ratio was 15:1.

Three rows of blind holes are processed in the middle area of the aluminum plate, the hole depth and diameter are both 4mm, and the hole spacing is 2mm.

After ball milling, the mixed particles are poured into the volatile organic solvent, mixed evenly and then added into the blind hole or groove; after the organic solvent volatilizes, fill again until it is filled;

Friction stir processing in-situ synthesis process parameters: rotation speed 600r/min, travel speed 40mm/min, press amount 0.1mm, inclination angle 2.5°, processing times 4 times, all 4 times along the same travel direction.

The microhardness of the obtained material composite layer is about 2.1 times that of the base material, and the high temperature wear resistance is 1.5 times that of the base material.

Claims (5)

1. aluminium oxide and zirconium diboride strengthen the preparation method of aluminum-based in-situ composite materials, it is characterized in that, comprise the following steps that

(1) by ZrO₂Granule mixes with B granule 11:2 in mass ratio, or by ZrO₂Granule and B₂O₃Granule 5:2 in mass ratio Mixing, and hybrid particles is carried out ball milling；

(2) with fine aluminium or aluminium alloy plate as matrix, in matrix surface or internal open channels or blind hole, hybrid particles is added groove or In blind hole, and tamp；

(3) the particles filled region to matrix is stirred friction processing, and stirring tool rotary speed is 600～3000r/min, advances Speed is 30～60mm/min, and volume under pressure is 0.05～0.6mm, and inclination angle is 0～3 °, and processing number of times is 3～8 times, processed ZrO in journey₂, B or B₂O₃Jointly there is chemical reaction in granule and aluminum substrate, finally gives aluminium oxide and strengthen aluminum base with zirconium diboride In-situ composite.

Aluminium oxide the most according to claim 1 strengthens the preparation method of aluminum-based in-situ composite materials, its feature with zirconium diboride Being that the Ball-milling Time described in step (1) is 1～10 hour, rotating speed is 50～100r/min, and ratio of grinding media to material is 5-15:1.

Aluminium oxide the most according to claim 1 strengthens the preparation method of aluminum-based in-situ composite materials, its feature with zirconium diboride It is, described ZrO₂Mean particle size is 10nm～between 10 μm, and purity is 90～99.9%, B or B₂O₃Granule is average Particle diameter is 10nm～between 100 μm, and purity is 90～99.9%.

Aluminium oxide the most according to claim 1 strengthens the preparation method of aluminum-based in-situ composite materials, its feature with zirconium diboride It is that before and after the processing of step (3), machine direction or the direction of rotation of twice are identical or contrary.

5. the aluminium oxide that prepared by the method described in claim 1 strengthens aluminum-based in-situ composite materials with zirconium diboride.