CN109385552B - Method for improving dry friction and wear performance of aluminum matrix composite - Google Patents
Method for improving dry friction and wear performance of aluminum matrix composite Download PDFInfo
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Abstract
A method for improving the dry friction and wear performance of an aluminum matrix composite belongs to the technical field of aluminum matrix composites. The invention aims at the technical difficulties that the carbon nano tube is difficult to be uniformly dispersed in the aluminum matrix and the interface bonding between the carbon nano tube and the aluminum matrix is weak. The method comprises the following steps: first, utilize
Weighing the mass of the carbon nano tube and the silicon carbide whisker; secondly, plating nickel on the surface of the carbon nano tube, placing the nickel in absolute ethyl alcohol, and performing ultrasonic dispersion to obtain a suspension A; thirdly, placing the silicon carbide whiskers into distilled water after acid washing, and ultrasonically dispersing to obtain a suspension B; dripping the suspension A into the suspension B, pouring a binder, and pressing the prefabricated block; putting the aluminum alloy into an extrusion casting die, heating and preserving heat, casting molten aluminum alloy, sealing, carrying out secondary pressurization, keeping pressure, cooling and then demolding; sixthly, hot extrusion; and seventhly, heat treatment. The invention improves the dry friction and wear performance of the aluminum matrix composite.
Description
Technical Field
The invention belongs to the technical field of aluminum matrix composite materials; in particular to a method for improving the dry friction and wear performance of an aluminum matrix composite.
Background
With the rapid development of the industries such as aerospace, rail transportation, automobile industry and the like, the demand for light-weight, high-strength and wear-resistant multifunctional materials is more and more obvious. The aluminum matrix composite material reinforced by the silicon carbide whiskers is widely researched and applied due to the characteristics of good wear resistance, low density, high thermal conductivity, low expansion coefficient and the like. However, with the increasing improvement of the wear resistance of materials, the aluminum matrix composite material reinforced by single silicon carbide whiskers cannot meet the requirements, and at present, the wear resistance of the material is mainly improved by adopting a mode of mixing and reinforcing two or more than two reinforcing phases at home and abroad.
Since their discovery in 1991, carbon nanotubes have gained much attention due to their ultra-high strength, modulus, thermal conductivity, etc., and are considered to be an ideal reinforcement material. The carbon nano-tube has self-lubricating property, and is uniformly distributed in the aluminum matrix, so that the wear rate and the friction coefficient of the composite material are reduced. It was found that the wear resistance of the composite material showed an increasing trend with increasing carbon nanotubes, but the wear resistance decreased dramatically when the carbon nanotubes agglomerated as the content of carbon nanotubes was increased. On the other hand, researches find that the wear resistance of the carbon nanotube reinforced aluminum matrix composite has critical load: when the load is less than the critical load, the wear rate and the friction coefficient of the composite material are obviously lower than those of the matrix alloy; above the critical load, the wear rate, coefficient of friction of the composite increases dramatically and is higher than that of the base alloy. This phenomenon occurs because the presence of carbon nanotubes provides a good lubricating effect when the load is small, and as the load increases, the problem of weak interface bonding due to poor wettability of carbon nanotubes with the aluminum matrix causes the carbon nanotubes to rapidly debond from the aluminum alloy, which weakens the lubricating effect, and the composite material also exhibits a large amount of subsurface fractures and spalling. Therefore, the dispersibility of the carbon nanotubes in the aluminum matrix and the interfacial bonding state therebetween are two major factors affecting the wear resistance of the composite material.
Disclosure of Invention
Aiming at the technical difficulties that the carbon nano tube is difficult to be uniformly dispersed in the aluminum matrix and the interface bonding between the carbon nano tube and the aluminum matrix is weak, a nickel layer is plated on the surface of the carbon nano tube by adopting a chemical nickel plating method, the aluminum matrix composite material reinforced by mixing the nickel-coated carbon nano tube and the silicon carbide whiskers is prepared by adopting an extrusion casting method, and the aluminum matrix composite material is subjected to hot extrusion and aging heat treatment to further improve the compactness, improve the hardness and the strength of the material and finally improve the dry friction and wear performance of the aluminum matrix composite material.
The method for improving the dry friction and wear performance of the aluminum-based composite material is completed by the following steps:
step one, respectively weighing the mass of the required carbon nano tube and the silicon carbide whisker according to the designed volume fraction, wherein the calculation formulas are all
Wherein VpreFor the volume of the precast block to be designed,
the volume fraction of the designed carbon nano tube or silicon carbide whisker is rho is the density of the designed carbon nano tube or silicon carbide whisker, wherein VpreIn units of cm3Rho is in g/cm3The density of the carbon nano tube is 1.3g/cm3The density of the silicon carbide crystal whisker is 3.2g/cm3M is in g;
step two, plating nickel on the surface of the carbon nano tube weighed in the step one, placing the carbon nano tube in absolute ethyl alcohol, and performing ultrasonic dispersion to obtain a suspension A;
step three, acid-washing the silicon carbide whiskers weighed in the step one, then putting the silicon carbide whiskers into distilled water, and ultrasonically dispersing the silicon carbide whiskers to a suspension state to obtain a suspension B;
step four, dripping the suspension A into the suspension B while ultrasonically dispersing, pouring a binder after mixing, continuously ultrasonically dispersing, mechanically stirring to be uniform under the condition of water bath heating, pouring into a mould, standing, removing upper-layer liquid, pressing by using a pressing die when no redundant liquid exists on the surface, drying at normal temperature in the shade, drying, sintering in vacuum at stages, and cooling along with a furnace to obtain a precast block;
putting the die into an extrusion casting die with a graphite gasket padded at the bottom, heating to 550-570 ℃, preserving heat, casting molten aluminum alloy into the die, sealing the die, applying pressure, performing secondary pressurization, cooling, maintaining pressure and demolding;
sixthly, sanding by using abrasive paper, cleaning by using ethanol, drying, and performing hot extrusion;
step seven, then heat treatment is carried out, namely the completion is completed;
wherein the binder in the fourth step is prepared from polyvinyl alcohol, silica sol, poly diallyl dimethyl ammonium chloride, glycerol and water.
Further, the acid washing in the third step is carried out by the following steps: the silicon carbide whisker is put into a mixed acid solution, the mixed acid solution is prepared by mixing hydrofluoric acid with the concentration of 14 percent (mass) and dilute nitric acid with the concentration of 10 percent (mass) according to the volume ratio of (5-10) to 1, carrying out ultrasonic treatment for 2-4 h at the temperature of 80 ℃, then standing for 1-2 h, removing the upper clear mixed acid solution, and then fully diluting and cleaning with distilled water until the pH value reaches 6.8-7.
Further limiting, the mass ratio of the volume of the distilled water in the third step to the silicon carbide whisker weighed in the first step is 100 mL: (10-20) g.
Further limiting, the dropping speed in the fourth step is 10-20 mL/min.
The adhesive is further limited to be prepared from polyvinyl alcohol, silica sol, poly diallyl dimethyl ammonium chloride, glycerol and water according to the mass ratio of 1:1:1:1 (10-15), and specifically comprises the following components: heating distilled water to 70-90 ℃, adding polyvinyl alcohol, continuously stirring to completely dissolve the polyvinyl alcohol, then adding glycerol, stirring uniformly, adding poly (diallyl dimethyl ammonium chloride), stirring uniformly, finally adding silica sol, stirring uniformly, cooling and standing.
Further limiting, the mass ratio of the volume of the binder in the fourth step to the silicon carbide whisker weighed in the first step is (1.6-2.4) mL:1 g.
And further limiting, pouring the binder in the fourth step, continuing ultrasonic dispersion for 1-1.5h, then heating in a water bath at 100 ℃, stirring uniformly at a mechanical stirring speed of 60rpm, pouring into a mold, standing for at least 10-24 h, removing upper-layer liquid, putting a pressure head into the mold when no excess liquid exists on the surface, pressurizing to the design height of the prefabricated block by using a jack, maintaining the pressure for 2-3 h, demolding, drying in the shade at normal temperature for 2-3 days, performing staged drying according to the steps of 50 ℃/5h, 75 ℃/10h, 100 ℃/5h and 120 ℃/5h, performing staged vacuum sintering according to the steps of 200 ℃/30min, 400 ℃/30min and 800 ℃/180min, wherein the sintering temperature rise rate is 3 ℃/min, and cooling along with the furnace to obtain the prefabricated block.
And further limiting, in the fifth step, the primary pressurizing pressure is 3-5 MPa, the pressure maintaining time is 15-20 seconds, the secondary pressurizing pressure is 100-120 MPa, and the composite material ingot is obtained after the mold is subjected to pressure maintaining until the temperature of the mold is lower than 100 ℃ and then the mold is removed.
Further defining, the six steps of hot extrusion process parameters: the extrusion ratio is selected from (16-25): 1, the extrusion pressure is 200MPa, and the temperature is 480-510 ℃.
Further limiting, the heat treatment method in the seventh step is heat treatment at 580 ℃, and furnace cooling is carried out after heat preservation is carried out for 1.5 hours; the heat treatment method in the seventh step can also be used for heat treatment for 1.5h at 580 ℃, then cooling to 160 ℃ at the speed of 4 ℃/min, preserving heat for 5h, and then cooling to room temperature along with the furnace.
The invention adopts a chemical nickel plating method to plate a nickel layer on the surface of the carbon nano tube, adopts an extrusion casting method to prepare the aluminum-based composite material reinforced by mixing the nickel-coated carbon nano tube and the silicon carbide whiskers, and carries out hot extrusion and heat treatment on the aluminum-based composite material to improve the dry friction and wear performance of the composite material. The silicon carbide whisker is different from the carbon nano tube, the whisker is easy to be wetted by the aluminum alloy, and according to the design of interface and performance, the mixing of the silicon carbide whisker and the carbon nano tube can not only prevent the carbon nano tube from agglomerating, but also adjust the volume fraction of the extrusion casting precast block and the distribution of the carbon nano tube, and ensure the infiltration of aluminum liquid. The existence of the nickel layer on the surface of the carbon nano tube can not only improve the wettability of the carbon nano tube with a matrix, but also reduce the high-temperature oxidation of the carbon nano tube and the interface reaction between the carbon nano tube and an aluminum matrix. The subsequent hot extrusion can reduce the holes in the composite material and improve the density. The aging treatment can separate out dispersed precipitated phases, thereby improving the performance of the material.
Drawings
FIG. 1 is a Scanning Electron Microscope (SEM) morphology photograph of a carbon nanotube after electroless nickel plating;
FIG. 2 is a Scanning Electron Microscope (SEM) morphology photograph of silicon carbide whiskers pretreated by the method of the invention;
FIG. 3 is a carbon nanotube and silicon carbide whisker hybrid reinforced precast block prepared by the method of the present invention;
FIG. 4 is a macroscopic picture of a hybrid reinforced 6061 aluminum matrix composite of carbon nanotubes and silicon carbide whiskers prepared by the method of the present invention, a) side, b) cross-section;
FIG. 5 is a macroscopic photograph of the hybrid reinforced 6061 aluminum-based composite of carbon nanotubes and silicon carbide whiskers prepared by the method of the present invention after hot extrusion;
FIG. 5 is a photomicrograph of the composite after hot extrusion;
FIG. 6 is a composite hot extrusion microstructure, a) perpendicular to the extrusion direction; b) parallel extrusion direction;
FIG. 7 is a graph comparing wear rates of composites in hot extrusion, hot extrusion soak heat treated, peak age hot extrusion, and peak age 6061 aluminum;
FIG. 8 is a comparison of Brinell hardness of 6061 aluminum alloy and different states of the composite after hot extrusion;
FIG. 9 is a wear scar topography of the hot extruded composite of FIG. 7, a) low power; b) high power;
FIG. 10 is the wear scar morphology of the composite of FIG. 7 in the peak age state, a) lower; b) high power.
Detailed Description
The first embodiment is as follows: the method for improving the dry friction and wear performance of the aluminum matrix composite material in the embodiment is completed by the following steps:
step one, respectively weighing the mass of the required carbon nano tube and the silicon carbide whisker according to the designed volume fraction, wherein the calculation formulas are all
Wherein VpreFor the volume of the precast block to be designed,
the volume fraction of the designed carbon nano tube or silicon carbide whisker is rho is the density of the designed carbon nano tube or silicon carbide whisker, wherein VpreIn units of cm3Rho is in g/cm3The density of the carbon nano tube is 1.3g/cm3The density of the silicon carbide crystal whisker is 3.2g/cm3M is in g;
design the size of the prefabricated block to be phi 50mm multiplied by 25mm, Vpre＝49cm3The volume fraction ratio of the carbon nanotubes to the silicon carbide whiskers is 1:1 and the total volume fraction is 20 vol.%, then
10 vol.%, 6.4g and 15.7g, respectively, were calculated as the mass required to obtain carbon nanotubes and silicon carbide whiskers。
Step two, nickel plating the surface of the carbon nano tube weighed in the step one, and the specific steps of nickel plating are ① pretreatment, namely 6.4g of the carbon nano tube is weighed according to the step 1), and is pretreated at room temperature, the pretreatment acid solution is a mixed acid solution with the volume ratio of conventional 98% concentrated sulfuric acid to 67.7% concentrated nitric acid being 3:1, in order to ensure the sufficient pretreatment of the carbon nano tube, the ratio of the carbon nano tube to the acid solution is less than 0.005g/ml, the pretreatment acid solution is 1300ml, the pretreatment time is 4h, the pretreatment process adopts ultrasonic treatment for 20min every 40min, the ultrasonic frequency is 50kHz, so as to ensure the sufficient mixing of the carbon nano tube and the acid solution, after the pretreatment is finished, the carbon nano tube is placed for 2h, the upper clear acid solution is removed, then distilled water is poured for dilution, then, the pretreated carbon nano tube is cleaned by adopting a vacuum filtration method, after the filtration process adopts a porous filter membrane with the pore diameter of 450nm, after the filtration process is finished, the filtration process, the carbon nano tube is placed in a beaker for continuous dilution, the further, the steps are repeated until the pH value of the carbon nano tube reaches 358, the distilled water with the distilled hydrochloric acid concentration of 2100, the distilled2·2H2Adding O into the solution to disperse uniformly, the concentration is 0.1mol/L, then transferring the solution into a gas washing bottle, adding 6.4g of carbon nano tube after acid treatment into the solution, filling nitrogen into the solution, sealing the container, carrying out ultrasonic treatment for 0.5h, carrying out frequency 50kHz, then cleaning for 5 times by adopting the suction filtration method, ③ activating, adding 2100ml of distilled water into the gas washing bottle, weighing 0.9g of PdCl2Adding into the above solution, mixing, adding carbon nanotube cleaned in step ② into a gas washing bottle, charging nitrogen, sealing, ultrasonically treating for 0.5 hr at 50kHz, cleaning for 5 times by the above suction filtration method, and chemically plating ④4·6H2O (0.2mol/L) and a reducing agent NaH2PO2·H2O (0.4mol/L), complex Na3C6H5O7·2H2O (0.1mol/L) and NH4Cl (1 mol/L). First Na3C6H5O7·2H2Dissolving O in water, and dissolving completely dissolved NiSO4·6H2Continuously stirring OAdding while stirring, and then adding completely dissolved NaH2PO2·H2O is slowly added to the above solution with stirring, and finally NH is added4And pouring Cl (dissolved) under stirring. After the plating solution is prepared, the carbon nano tube cleaned after sensitization and activation is added into the plating solution, and the plating is carried out under the ultrasonic oscillation condition. The plating process is carried out in batches by taking 2-2.2g as a unit, and the ratio of the carbon nano tube to the plating solution is 1 g: 600 mL. Adjusting pH value with ammonia water during plating process, keeping pH value at 9.5, plating for 2h, cleaning by the above-mentioned suction filtration method until pH value reaches 6.8 to obtain carbon nanotube with nickel-plated surface layer, placing in 50mL absolute ethyl alcohol, performing ultrasonic dispersion under ultrasonic frequency of 50kHz, and suspending liquid A;
step three, putting the silicon carbide whisker and the silicon carbide whisker weighed in the step one into a mixed acid solution, wherein the mixed acid solution is prepared by mixing hydrofluoric acid with the concentration of 14 percent (mass) and dilute nitric acid with the concentration of 10 percent (mass) according to the volume ratio of 10:1, performing ultrasonic treatment for 2 hours at the temperature of 80 ℃, standing for 1 hour, removing the upper clear mixed acid solution, fully diluting and cleaning with distilled water until the pH value reaches 6.8, then putting into 100mL of distilled water, and performing ultrasonic dispersion at the ultrasonic frequency of 50kHz to a suspension state to obtain a suspension B;
step four, dripping the suspension A into the suspension B at the speed of 20mL/min while performing ultrasonic dispersion at the frequency of 50kHz, pouring a binder after mixing, continuing ultrasonic dispersion for 1.5h, then mechanically stirring to be uniform under the heating of 100 ℃ water bath, pouring into a mold, standing for 10h, removing upper-layer liquid, putting a pressure head into the mold when no redundant liquid exists on the surface, pressurizing to the design height of the prefabricated block by adopting a jack, maintaining the pressure for 3h, demolding, drying in the shade at normal temperature for 3 days, performing staged drying according to the steps of 50 ℃/5h, 75 ℃/10h, 100 ℃/5h and 120 ℃/5h, performing staged vacuum sintering according to the steps of 200 ℃/30min, 400 ℃/30min and 800 ℃/180min, wherein the sintering temperature rise speed is 3 ℃/min, and cooling along with the furnace to obtain the prefabricated block;
the mass ratio of the volume of the binder in the fourth step to the silicon carbide crystal whisker weighed in the first step is 2mL:1g
The adhesive is prepared from polyvinyl alcohol, silica sol, poly (diallyl dimethyl ammonium chloride), glycerol and water according to the mass ratio of 1:1:1:1:15, and the adhesive preparation step comprises the steps of heating distilled water to 85 ℃, adding the polyvinyl alcohol, continuously stirring to completely dissolve the polyvinyl alcohol, then adding the glycerol, uniformly stirring, adding the poly (diallyl dimethyl ammonium chloride), uniformly stirring, finally adding the silica sol, uniformly stirring, cooling and standing.
And step five, placing the die into a squeeze casting die with a graphite gasket at the bottom, heating to 550 ℃, preserving heat for 1h, simultaneously weighing aluminum alloy with the volume ratio of 2:1 to the prefabricated block, melting the aluminum alloy at 780 ℃ to obtain molten aluminum alloy, casting the molten aluminum alloy into the die, sealing the die by using a graphite sealing gasket, and then applying pressure. And a secondary pressurization method is adopted in the whole die casting process, the primary pressure is 3MPa, the pressure maintaining time is 20 seconds, the secondary pressurization is 120MPa, the secondary pressurization is continuously carried out under 120MPa until the die is cooled to 80 ℃, and then the die is removed, so that the carbon nano tube and silicon carbide whisker hybrid reinforced aluminum matrix composite is obtained. Due to the existence of the nickel layer on the surface of the carbon nano tube, the reaction degree of the carbon nano tube and the aluminum matrix in the aluminum liquid casting process is reduced.
And sixthly, polishing with 600# abrasive paper, cleaning with ethanol, drying, selecting an extrusion ratio of 16:1, coating graphite lubricating oil (prepared by uniformly stirring lubricating oil and graphite powder with the granularity of 5-50 mu m, wherein 2-5 g of graphite powder is added to every 1mL of lubricating oil) on the inner layer of a corresponding extrusion cup, putting the treated cast composite material above the extrusion cup, putting the treated cast composite material in a resistance heating furnace, jointly preheating for 1h at 510 ℃, and then extruding by using a four-column press with the extrusion pressure of 200MPa to obtain the extruded composite material. Due to the existence of the nickel layer on the surface of the carbon nano tube, the reaction of the carbon nano tube and the aluminum matrix in the hot extrusion process is reduced.
And step seven, performing high-temperature heat exposure treatment, namely performing heat preservation heat treatment on the extruded composite material at the heat treatment temperature of 580 ℃ for 1.5h, and then cooling along with a furnace, in order to further promote the diffusion of interface elements among the reinforcement, the nickel layer and the matrix and improve the interface bonding strength.
The second embodiment is as follows: the difference between the embodiment and the first embodiment is that in the seventh step, the high-temperature heat exposure superposition peak aging treatment is carried out, the heat treatment process is 580 ℃/1.5h and 160 ℃/5h, the cooling rate between the two temperatures is 4 ℃/min, and finally the temperature is cooled to the room temperature along with the furnace.
The Scanning Electron Microscope (SEM) morphology photograph of the electroless nickel-plated carbon nanotube in this embodiment is shown in fig. 1. It can be seen from fig. 1 that a uniform nickel metal layer is attached to the surface of the carbon nanotubes, and that a small amount of nickel particles exist between the carbon nanotubes.
The silicon carbide whisker pretreated by the method of the embodiment has good whisker dispersibility and less impurities as shown in figure 2.
Fig. 3 shows a carbon nanotube and silicon carbide whisker hybrid reinforced precast block prepared by the method of the present embodiment. Macroscopic observation shows that the precast block has good shape and no cracking phenomenon.
A macroscopic picture of the 6061 aluminum-based composite material hybrid-reinforced by the carbon nanotube and the silicon carbide whisker prepared by the method of the embodiment is shown in fig. 4, and the final size of the as-cast composite material is phi 55mm × 25mm (the carbon nanotube: the silicon carbide whisker is 1:1, and the total volume fraction is 20 vol%). The surface of the as-cast composite material is seen to present metallic luster, no macroscopic visible aluminum strip is appeared, and the aluminum liquid is well infiltrated.
A macroscopic photograph of the hybrid reinforced 6061 aluminum-based composite material of carbon nanotubes and silicon carbide whiskers prepared by the method of the present embodiment after hot extrusion is shown in fig. 5. The cast composite material has casting defects, and the density of the composite material can be improved through hot extrusion, so that the hardness and the strength are improved. On the other hand, the hot extrusion can ensure that the reinforcing bodies are directionally distributed, promote the uniform distribution of the reinforcing bodies, and simultaneously ensure that the aluminum matrix is subjected to recovery recrystallization and grain refinement. As can be seen from fig. 5, the surface state of the extruded composite material was good except for a few micro cracks.
The morphology of the SEM of the extruded composite material prepared by the embodiment after the polished surface is corroded in the direction perpendicular to and parallel to the extrusion direction is shown in FIG. 6. As can be seen from fig. 6a), the reinforcement is uniformly distributed in the composite after hot extrusion. It can be seen in fig. 6b) that the whiskers are clearly aligned along the extrusion direction and are longer, illustrating that the whiskers are prevented from being largely broken during extrusion due to the intermixing with the carbon nanotubes.
A comparison of the wear rates of the hot extruded, hot extruded and temper heat treated composites and the 6061 aluminum peak aged composite is shown in FIG. 7. The friction wear test was performed on a CJS111A type friction wear tester with a ball/flat contact for the friction pair. The main process is that a test sample is fixed on a chassis of a testing machine, the chassis performs circular motion at a certain speed, so that grinding balls scratch on the test sample, and the grinding balls are made of GCr 15. The relative slip rate shown in FIG. 7 was 0.053m/s with a load of 1.96N. As can be seen from FIG. 7, the wear resistance of the extruded composite is significantly higher than that of the matrix aluminum alloy. And the wear resistance after heat preservation heat treatment is higher than that in a hot extrusion state, and the peak aging state is higher than that in a heat preservation heat treatment state. This is primarily related to interfacial bonding, where the extruded material has the weakest strength than the latter, and the wear surface will be uneven during frictional wear, resulting in increased surface roughness and hence increased wear rate. After heat preservation and heat treatment, the interface bonding strength between the reinforcement and the matrix is improved, so that the surface roughness is reduced in the friction and wear process, and the wear rate is greatly reduced. Secondly, the wear rate is also related to the hardness of the material. FIG. 8 is the Brinell hardness of the four-phase material, and the peak-aged composite material after hot extrusion favors the precipitation of finely dispersed second phases, increasing the strength and hardness of the composite material, thus demonstrating the wear rate results in FIG. 7.
Fig. 9 and 10 are wear scar topographies for the hot extruded state of embodiment one and the peak aged state of embodiment two of fig. 7, respectively. It can be seen from the figure that under the test conditions, both are mainly abrasive wear mechanisms, and the surface-detached reinforcement is regarded as abrasive particles participating in three-body wear due to the existence of silicon carbide whiskers, and from the comparison of fig. 9 and 10, the surface wear degree of the composite material in the peak aging state is obviously lower than that in the hot extrusion state, because the fracture detachment of the whiskers is limited by the reinforcement of the interface bonding of the carbon nanotubes and the aluminum matrix, and the quantity of the abrasive particles on the friction surface of the composite material is reduced. In addition, as the strength and hardness of the composite material increases, the depth of penetration of the abrasive particles into the matrix of the composite material during frictional wear will decrease, resulting in smaller surface scratches and furrows in width and depth. As can be seen in FIGS. 9 and 10, the composite surface scratches and furrows were reduced in size in the peak aged state, indicating that the surface was worn to a lesser extent by the abrasive particles and was more resistant to wear. In addition, sheet layer structures are formed on the surface of the material surface layer after strain hardening is generated through repeated plastic deformation in the friction and wear process, but the carbon nano tubes play a role in lubrication in the friction and wear process, and the wear resistance of the carbon nano tubes also enhances the plastic rheological resistance of the surface of the composite material, so that the wear resistance of the composite material is further improved.
Claims (7)
1. A method for improving the dry friction and wear performance of an aluminum matrix composite is characterized by comprising the following steps:
step one, respectively weighing the mass of the required carbon nano tube and the silicon carbide whisker according to the designed volume fraction, wherein the calculation formulas are all
Wherein VpreFor the volume of the precast block to be designed,
the volume fraction of the designed carbon nano tube or silicon carbide whisker is rho is the density of the designed carbon nano tube or silicon carbide whisker, wherein VpreIn units of cm3Rho is in g/cm3The density of the carbon nano tube is 1.3g/cm3The density of the silicon carbide crystal whisker is 3.2g/cm3M is in g;
step two, plating nickel on the surface of the carbon nano tube weighed in the step one, placing the carbon nano tube in absolute ethyl alcohol, and performing ultrasonic dispersion to obtain a suspension A;
step three, acid-washing the silicon carbide whiskers weighed in the step one, then putting the silicon carbide whiskers into distilled water, and ultrasonically dispersing the silicon carbide whiskers to a suspension state to obtain a suspension B;
step four, dripping the suspension A into the suspension B while performing ultrasonic dispersion, pouring a binder after mixing, continuing ultrasonic dispersion for 1-1.5h, heating in a water bath at 100 ℃, stirring uniformly at a mechanical stirring speed of 60rpm, pouring into a mold, standing for 10-24 h, removing upper-layer liquid, putting a pressure head into the mold when no excess liquid exists on the surface, pressurizing to the design height of the prefabricated block by using a jack, maintaining the pressure for 2-3 h, demolding, drying in the shade at normal temperature for 2-3 days, performing staged drying according to the steps of 50 ℃/5h, 75 ℃/10h, 100 ℃/5h and 120 ℃/5h, performing staged vacuum sintering according to the steps of 200 ℃/30min, 400 ℃/30min and 800 ℃/180min, wherein the sintering temperature rise rate is 3 ℃/min, and performing furnace cooling after sintering to obtain the prefabricated block;
putting the precast block into an extrusion casting mold with a graphite gasket padded at the bottom, heating to 550-570 ℃, preserving heat, casting molten aluminum alloy into the mold, sealing the mold, applying pressure, performing secondary pressurization, maintaining the pressure, cooling and then demolding;
step six, sanding with abrasive paper, cleaning with ethanol, drying, hot extruding, wherein the hot extruding process parameters are as follows: the extrusion ratio is selected from (16-25) to 1, the extrusion pressure is 200MPa, and the temperature is 480-510 ℃;
step seven, heat treatment: firstly, carrying out heat treatment for 1.5h at 580 ℃, then cooling to 160 ℃ at the speed of 4 ℃/min, keeping the temperature for 5h, and then cooling to room temperature along with the furnace to complete the process;
wherein the binder in the fourth step is prepared from polyvinyl alcohol, silica sol, poly diallyl dimethyl ammonium chloride, glycerol and water.
2. The method of claim 1, wherein the acid washing in step three is performed by: the silicon carbide whisker is put into a mixed acid solution, the mixed acid solution is prepared by mixing hydrofluoric acid with the concentration of 14 percent (mass) and dilute nitric acid with the concentration of 10 percent (mass) according to the volume ratio of (5-10) to 1, carrying out ultrasonic treatment for 2-4 h at the temperature of 80 ℃, then standing for 1-2 h, removing the upper clear mixed acid solution, and then fully diluting and cleaning with distilled water until the pH value reaches 6.8-7.
3. The method according to claim 1, wherein the mass ratio of the volume of the distilled water in the third step to the silicon carbide whisker weighed in the first step is 100 mL: (10-20) g.
4. The method according to claim 1, wherein the dropping rate in the fourth step is 10 to 20 mL/min.
5. The method according to claim 1, wherein the binder is prepared from polyvinyl alcohol, silica sol, poly (diallyldimethylammonium chloride), glycerol and water according to a mass ratio of 1:1:1:1 (10-15), and specifically comprises: heating distilled water to 70-90 ℃, adding polyvinyl alcohol, continuously stirring to completely dissolve the polyvinyl alcohol, then adding glycerol, stirring uniformly, adding poly (diallyl dimethyl ammonium chloride), stirring uniformly, finally adding silica sol, stirring uniformly, cooling and standing.
6. The method according to claim 1, wherein the mass ratio of the volume of the binder in the fourth step to the silicon carbide whisker weighed in the first step is (1.6-2.4) mL:1 g.
7. The method according to claim 1, characterized in that in the fifth step, secondary pressurization is adopted, primary pressurization is carried out for 3-5 MPa in the process of impregnating pores of the precast block with the molten aluminum alloy, the pressure maintaining time is 15-20 seconds, secondary pressurization is carried out for 100-120 MPa in the solidification process after the impregnation is finished, the mold is removed after the pressure maintaining is carried out until the temperature of the mold is lower than 100 ℃, and then the composite material ingot is obtained.
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| CN112453385B (en) * | 2020-11-23 | 2022-09-27 | 成都威士达粉末冶金有限公司 | Powder metallurgy composite material with high composite ratio and manufacturing method thereof |
| CN112941384A (en) * | 2021-01-11 | 2021-06-11 | 南昌大学 | Method for preparing carbon nano material reinforced AZ91 alloy semi-solid slurry |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1804099A (en) * | 2005-12-28 | 2006-07-19 | 哈尔滨工业大学 | Carbon nanotube metal based composite materials and process for preparing the same |
| CN101724795A (en) * | 2009-12-16 | 2010-06-09 | 哈尔滨工业大学 | Method for improving strength and plasticity of whisker reinforced pure aluminium-based composite material |
| CN101876040A (en) * | 2009-11-17 | 2010-11-03 | 哈尔滨工业大学 | Method for preparing carbon nanotube and aluminum borate whisker hybrid reinforced aluminum-matrix composite material |
| CN102080197A (en) * | 2010-12-16 | 2011-06-01 | 哈尔滨工业大学 | Method for coating surface of reinforcement in composite material |
| WO2011149931A1 (en) * | 2010-05-24 | 2011-12-01 | Applied Nanotech Holdings, Inc. | Thermal management composite materials |
| CN106119741A (en) * | 2016-08-14 | 2016-11-16 | 天津联科技有限公司 | A kind of CNT and the preparation method of aluminum borate whisker hybrid reinforced aluminum-matrix composite material |
-
2018
- 2018-10-31 CN CN201811286124.5A patent/CN109385552B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1804099A (en) * | 2005-12-28 | 2006-07-19 | 哈尔滨工业大学 | Carbon nanotube metal based composite materials and process for preparing the same |
| CN101876040A (en) * | 2009-11-17 | 2010-11-03 | 哈尔滨工业大学 | Method for preparing carbon nanotube and aluminum borate whisker hybrid reinforced aluminum-matrix composite material |
| CN101724795A (en) * | 2009-12-16 | 2010-06-09 | 哈尔滨工业大学 | Method for improving strength and plasticity of whisker reinforced pure aluminium-based composite material |
| WO2011149931A1 (en) * | 2010-05-24 | 2011-12-01 | Applied Nanotech Holdings, Inc. | Thermal management composite materials |
| CN102080197A (en) * | 2010-12-16 | 2011-06-01 | 哈尔滨工业大学 | Method for coating surface of reinforcement in composite material |
| CN106119741A (en) * | 2016-08-14 | 2016-11-16 | 天津联科技有限公司 | A kind of CNT and the preparation method of aluminum borate whisker hybrid reinforced aluminum-matrix composite material |
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