CN110747361A - Preparation method of titanium boride reinforced aluminum-based composite material based on ultrasonic and mechanical stirring - Google Patents

Abstract

The invention relates to the field of metal alloy material preparation, and discloses a method for preparing a titanium boride reinforced aluminum-based composite material based on ultrasound and mechanical stirring. Mixing and drying for standby use; the aluminum alloy ingot is placed in a graphite crucible, heated until the temperature of the aluminum melt is stable at 800-850 ° C, and the dried mixed powder is added to the aluminum melt, and mechanically stirred, until the temperature of the composite material is When cooled to 720°C, skim off the scum, pour it into a graphite mold to cool; put the cooled sample back into the graphite crucible, heat it with a resistance furnace until it melts, and add a high-energy ultrasonic radiation rod to the mixed melt for mixing. The melt was ultrasonically treated, and after the ultrasonic treatment time was over, the mixed melt was poured into a graphite mold, and the sample was immediately cooled with liquid nitrogen, so that the nano _- TiB particles in the obtained nano-TiB reinforced aluminum matrix composite material were uniformly distributed. , without agglomeration.

Description

Preparation method of titanium boride reinforced aluminum matrix composites based on ultrasonic and mechanical stirring

technical field

The invention relates to the field of metal alloy material preparation, in particular to a method for preparing a titanium boride reinforced aluminum matrix composite material based on ultrasound and mechanical stirring.

Background technique

Ceramic particle-reinforced aluminum matrix composites have the advantages of high specific modulus, high hardness and high wear resistance, and are widely used in aerospace, automobile manufacturing and other fields. Titanium boride (TiB ₂ ) has the characteristics of high hardness, high thermal stability, corrosion resistance, no interfacial reaction with aluminum melt, and good chemical stability, so it has become a hot spot in the research of particle-reinforced aluminum matrix composites. TiB ₂ nanoparticles can significantly improve the elastic modulus, yield strength, wear resistance and other properties of the matrix by being closely combined with the alloy matrix.

However, a large number of studies have shown that TiB ₂ nanoparticles have poor wettability with the aluminum melt prepared by the traditional external addition method, and it is difficult to enter the interior of the aluminum melt; TiB ₂ nanoparticles prepared by the in situ method are in the aluminum melt. There are problems such as particle agglomeration and low particle yield, which adversely affect the performance improvement of aluminum matrix composites.

SUMMARY OF THE INVENTION

Based on the above problems, the present invention provides a method for preparing a titanium boride reinforced aluminum-based composite material based on ultrasonic and mechanical stirring. First, the reaction salt and the cosolvent powder are uniformly mixed, and then the reaction salt and the cosolvent powder are added to the aluminum melt. At the same time, a stirrer is used to increase the contact area between the molten reaction salt and the aluminum melt by mechanical stirring, so as to speed up the reaction rate, promote the reaction, and increase the yield of reactants. The sample was remelted again, and the remelted mixed melt was ultrasonically treated with a high-energy ultrasonic radiation rod, then poured into a mold and cooled with liquid nitrogen to finally obtain nano-TiB ₂ in nano-titanium boride reinforced aluminum matrix composites. The particles are evenly distributed and there is no agglomeration.

For solving the above technical problems, the technical scheme adopted in the present invention is:

The preparation method of titanium boride reinforced aluminum matrix composite material based on ultrasonic and mechanical stirring includes the following steps:

S1: Weigh a certain quality of aluminum alloy ingots for use;

S2: Weigh out the potassium fluorotitanate and potassium fluoroborate reaction salt powders according to the pre-generated _3vol % TiB particles in the reinforced aluminum matrix composite material, and the mass of the cosolvent sodium fluoroaluminate powder is potassium fluorotitanate, potassium fluoroborate 10% of the total mass of the two reaction salts are fully mixed by mechanical stirring, and dried in a drying oven at 200-300°C for 1-2 hours for use;

S3: Put the weighed aluminum alloy ingot into a graphite crucible, and heat it with a resistance furnace. After the temperature of the aluminum melt is stabilized at 800-850°C, the dried mixed powder is added to the aluminum melt, and the Mechanical stirring, when the temperature of the composite material is cooled to 720 °C, skim off the scum, pour it into a graphite mold preheated at 300 °C and cool;

S4: Put the cooled sample back into the graphite crucible, heat it with a resistance furnace to 720°C to melt to form a mixed melt, add a high-energy ultrasonic radiation rod to the mixed melt, and control the ultrasonic frequency to be 18-20KHz and the power to be 1-2KW , the amplitude is 10 ~ 15μm, the immersion depth of the ultrasonic radiation rod is 15 ~ 25mm, and the ultrasonic treatment time is 30 ~ 240s;

S5: After the ultrasonic treatment time is over, the mixed melt is poured into a graphite mold preheated at 300° C., and cooled with liquid nitrogen to obtain the final nano-titanium boride reinforced aluminum matrix composite material.

Further, one end of the ultrasonic radiation rod is connected to the ultrasonic transducer, and the other end is immersed in the mixed melt in the graphite crucible; the transducer is electrically connected to the ultrasonic power source.

Further, the aluminum alloy ingot is 2Al4 aluminum alloy.

Further, in step S3, the addition time of the reaction salt and the cosolvent is controlled to be 15 to 25s, and a stirrer is used for mechanical stirring when the reaction salt and the cosolvent are added, the stirring speed is 150rpm, and the stirring time is 30min.

Further, a thermocouple for measuring the temperature of the mixed melt is arranged in the graphite crucible, and the signal output end of the thermocouple is electrically connected to a data collector, and the data collector is communicatively connected to a computer terminal.

Compared with the prior art, the beneficial effects of the present invention are:

1) First uniformly mix the reaction salt and the cosolvent powder, then add the reaction salt and the cosolvent powder into the aluminum melt, and at the same time use a stirrer to increase the contact between the molten state of the reaction salt and the aluminum melt by mechanical stirring area, speed up the reaction rate, promote the reaction, increase the yield of reactants, and then skim off the scum and pour into the mold to cool; remelt the cooled sample, and use a high-energy ultrasonic radiation rod to remelt the mixed melt. Ultrasonic treatment, followed by casting into a mold and cooling with liquid nitrogen, finally obtained nano-TiB ₂ particles in the nano-TiB-reinforced aluminum matrix composite with uniform distribution and no agglomeration.

₂ ) The fine network Cu2Al phase in the microstructure of the aluminum matrix composite material obtained by the present invention is distributed in the aluminum matrix, and the nano _- TiB2 particles are evenly distributed without agglomeration; the process is safe, reliable, cost-effective and simple to operate.

3) The mechanical properties of the composite material are tested. Compared with the composite material prepared by the ordinary method, the performance of the composite material prepared by the technical solution of this patent is greatly improved, and its yield strength, tensile strength and hardness are respectively improved. 54%, 21% and 27%, while the wear quality is reduced by 37% and the wear resistance is improved.

Description of drawings

Fig. 1 is the schematic diagram of mechanical stirring for preparing TiB ₂ /2A14 aluminum matrix composite material according to the present invention;

FIG. 2 is a schematic diagram of ultrasonic treatment for preparing TiB ₂ /2A14 aluminum matrix composite material according to the present invention;

Fig. 3 is the microstructure of the TiB ₂ /2A14 aluminum matrix composite material prepared by the present invention;

Among them, 1, stirrer; 2, graphite crucible; 3, reaction salt; 4, aluminum melt; 5, mixed melt; 6, resistance furnace; 7, ultrasonic power supply; 8, transducer; 9, ultrasonic radiation rod ; 10. Thermocouple; 11. Data collector; 12. Computer terminal.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the examples. limit.

Example 1:

Referring to Fig. 1 and Fig. 2, the preparation method of titanium boride reinforced aluminum matrix composite material based on ultrasonic and mechanical stirring includes the following steps:

S1: Weigh a certain quality of aluminum alloy ingots for use;

S2: Weigh the potassium fluorotitanate and potassium fluoroborate reaction salt ₃ powders according to the pre-generated 3vol% TiB particles in the reinforced aluminum matrix composite material, and the mass of the cosolvent sodium fluoroaluminate powder is potassium fluorotitanate, fluoroboric acid 10% of the total mass of the two reactive salts of potassium 3 is fully mixed by mechanical stirring, and dried in a drying oven at 200 to 300 ° C for 1 to 2 hours for later use;

S3: Put the weighed aluminum alloy ingot into the graphite crucible 2, heat with the resistance furnace 6, until the temperature of the aluminum melt 4 is stabilized at 800-850 ° C, add the dried mixed powder to the aluminum melt 4 and mechanical stirring. When the temperature of the composite material is cooled to 720°C, the scum is removed, poured into a graphite mold preheated at 300°C and cooled;

S4: Put the cooled sample into the graphite crucible 2 again, heat it with the resistance furnace 6 to 720°C and melt to form the mixed melt 5, add the high-energy ultrasonic radiation rod 9 to the mixed melt 5, and control the ultrasonic frequency to be 18-20KHz, The power is 1-2KW, the amplitude is 10-15μm, the immersion depth of the ultrasonic radiation rod 9 is 15-25mm, and the ultrasonic treatment time is 30-240s;

S5: After the ultrasonic treatment time is over, pour the mixed melt 5 into a graphite mold preheated at 300° C., and cool with liquid nitrogen to obtain the final nano-titanium boride reinforced aluminum matrix composite material.

In this embodiment, the powders of potassium fluorotitanate (K ₂ TiF ₆ ), potassium fluoroborate (KBF ₄ ), and sodium fluoroaluminate (Na ₃ AlF ₆ ) as co-solvents are all chemically pure grades. The following in situ chemical reactions occur in 4:

3K ₂ TiF ₆ +6KBF ₄ +10Al→3TiB ₂ +9KAlF ₄ +K ₃ AlF ₆

Through this reaction, nano-scale TiB ₂ particles with no pollution on the surface can be generated, which greatly improves the wettability of the nanoparticles and the aluminum melt 4 and facilitates the interface bonding between the particles and the matrix. The cavitation effect and acoustic flow effect produced by high-energy ultrasound in the aluminum melt 4 can promote the wetting of the particles, break up the agglomeration of the particles, and greatly help the uniform distribution of the particles. Using liquid nitrogen cooling can obtain aluminum-based composite materials with uniform distribution of particles under the action of ultrasound, avoiding the phenomenon of particle re-agglomeration caused by the sedimentation of particles due to gravity under the traditional cooling method. The fine network Cu ₂ Al phase in the microstructure of the aluminum matrix composite material obtained in this example is distributed in the aluminum matrix, and the nano-TiB ₂ particles are uniformly distributed and have no agglomeration phenomenon. This process is safe, reliable, cost-effective and simple to operate.

In this embodiment, in step S3, the addition time of the reaction salt 3 and the co-solvent is controlled to be 15 to 25s, and the stirrer 1 is used for mechanical stirring when the reaction salt 3 and the co-solvent are added, the stirring speed is 150 rpm, and the stirring time is 30 min.

One end of the ultrasonic radiation rod 9 is connected to the ultrasonic transducer 8 , and the other end is immersed in the mixed melt 5 in the graphite crucible 2 ; the transducer 8 is electrically connected to the ultrasonic power source 7 . The ultrasonic power source 7 provides the working current for the transducer 8, and the transducer 8 converts the electrical energy into the mechanical energy of ultrasonic vibration. After the ultrasonic radiation rod 9 is immersed in the composite melt, the nano _- TiB particles in the composite melt are treated by ultrasonic waves. The aluminum melt 4 is uniformly dispersed, and no agglomeration occurs.

The graphite crucible 2 in this embodiment is provided with a thermocouple 10 for measuring the temperature of the mixed melt 5 , and the signal output end of the thermocouple 10 is electrically connected to the data collector 11 , and the data collector 11 communicates with the computer terminal 12 connect. The temperature of the melt in the process of heating, stirring and ultrasonic treatment is collected by the thermocouple 10, processed by the data collector 11 and converted into a temperature value and transmitted to the computer terminal 12 for display, so as to facilitate the operator to understand the temperature in the preparation process. Record and control accordingly.

Example 2:

Referring to Fig. 1 and Fig. 2, first take by weighing the 2A14 aluminum alloy ingot of 500g, and the 2A14 aluminum alloy ingot that is weighed is put into the graphite crucible 2, heated to melting with the resistance furnace 6, simultaneously according to the in-situ reaction equation , according to the pre-generated 3vol% TiB ₂ particles, the potassium fluorotitanate (K ₂ TiF ₆ ) and potassium fluoroborate (KBF ₄ ) reaction salt 3 powders were weighed to be 88.33g and 92.75g respectively, then the cosolvent sodium fluoroaluminate ( The mass of Na ₃ AlF ₆ ) was 18.11 g. After fully mixing by mechanical stirring, it is dried in a drying furnace at 200°C for 2 hours. When the temperature of the aluminum melt 4 is stabilized at 820°C, the dried mixed powder is added to the aluminum melt 4. The addition time is 15s. During the process, mechanical stirring was introduced, the stirring speed was 150 rpm, and the stirring time was 30 minutes; when the temperature of the composite material was cooled to 720 °C, the scum was removed, and it was poured into a graphite mold preheated at 300 °C for cooling. Put the cooled sample back into the graphite crucible 2, heat it with a resistance furnace 6 to 720°C to melt to form a mixed melt 5, add high-energy ultrasound to the mixed melt 5, the ultrasonic frequency is 20KHz, the power is 1KW, and the amplitude is 12 μm. The immersion depth of the ultrasonic radiation rod 9 is 20mm, and the ultrasonic treatment time is 90s. After the ultrasonic treatment time is over, the mixed melt 5 is poured into a graphite mold preheated at 300° C. and cooled with liquid nitrogen to obtain the final nanometer titanium boride reinforced aluminum base. composite material.

Example 3:

Referring to Fig. 1-3, first take by weighing the 2A14 aluminum alloy ingot of 550g, and put the 2A14 aluminum alloy ingot that has been weighed into the graphite crucible 2, be heated to melting with a resistance furnace 6, and simultaneously according to the in-situ reaction equation, Weigh potassium fluorotitanate (K ₂ TiF ₆ ) and potassium fluoroborate (KBF ₄ ) reaction salt 3 powders according to the pre-generated 3vol% TiB ₂ particles, respectively 97.17 g and 102.03 g, then the cosolvent sodium fluoroaluminate (Na ₃ AlF ₆ ) had a mass of 19.92 g. After fully mixing by mechanical stirring, it is dried in a drying furnace at 300°C for 1 hour. When the temperature of the aluminum melt 4 is stabilized at 830°C, the dried mixed powder is added to the aluminum melt 4 for 20s. In the process, mechanical stirring was introduced, the stirring speed was 150 rpm, and the stirring time was 30 minutes; when the temperature of the composite material was cooled to 720 °C, the scum was removed, and it was poured into a graphite mold preheated at 300 °C for cooling. Put the cooled sample back into the graphite crucible 2, heat it with a resistance furnace 6 to 720°C to melt to form a mixed melt 5, add high-energy ultrasound to the mixed melt 5, the ultrasonic frequency is 19KHz, the power is 2KW, and the amplitude is 15μm. The immersion depth of the ultrasonic radiation rod 9 is 25 mm, and the ultrasonic treatment time is 120 s. After the ultrasonic treatment time is over, the mixed melt 5 is poured into a graphite mold preheated at 300 ° C and cooled with liquid nitrogen to obtain the final nano-titanium boride reinforced aluminum. Matrix composites.

The microstructure of the as-cast TiB ₂ /2A14 aluminum matrix composite material, according to Figure 3, there are no coarse dendritic primary crystals in the structure of the aluminum matrix composite material, and the primary α-Al phase is under the effect of TiB ₂ particles and ultrasonic cavitation. , was significantly refined. Under the synergistic effect of ultrasonic cavitation and ultrasonic acoustic flow, there is no obvious particle agglomeration in the composite, and the _TiB particles are uniformly distributed in the tissue.

By testing the mechanical properties of the composite material obtained in this example, compared with the composite material prepared by the common method, the performance of the composite material prepared by this technical solution is greatly improved, and its yield strength, tensile strength and hardness are respectively improved. 54%, 21% and 27%, while the wear quality is reduced by 37% and the wear resistance is improved.

The above is an embodiment of the present invention. The above examples and the specific parameters in the examples are only to clearly describe the invention verification process, not to limit the scope of patent protection of the present invention. The scope of patent protection of the present invention is still based on the claims. Equivalent structural changes made in the contents of the description shall be included within the protection scope of the present invention.

Claims (5)

1. the titanium boride reinforced aluminum matrix composite material preparation method based on ultrasonic and mechanical stirring, is characterized in that, comprises the steps: S1: Weigh a certain quality of aluminum alloy ingots for use; S2: Weigh out the potassium fluorotitanate and potassium fluoroborate reaction salt powders according to the pre-generated _3vol % TiB particles in the reinforced aluminum matrix composite material, and the mass of the cosolvent sodium fluoroaluminate powder is potassium fluorotitanate, potassium fluoroborate 10% of the total mass of the two reaction salts are fully mixed by mechanical stirring, and dried in a drying oven at 200-300°C for 1-2 hours for use; S3: Put the weighed aluminum alloy ingot into a graphite crucible, and heat it with a resistance furnace. After the temperature of the aluminum melt is stabilized at 800-850°C, the dried mixed powder is added to the aluminum melt, and the Mechanical stirring, when the temperature of the composite material is cooled to 720 °C, skim off the scum, pour it into a graphite mold preheated at 300 °C and cool; S4: Put the cooled sample back into the graphite crucible, heat it with a resistance furnace to 720°C to melt to form a mixed melt, add a high-energy ultrasonic radiation rod to the mixed melt, and control the ultrasonic frequency to be 18-20KHz and the power to be 1-2KW , the amplitude is 10 ~ 15μm, the immersion depth of the ultrasonic radiation rod is 15 ~ 25mm, and the ultrasonic treatment time is 30 ~ 240s; S5: After the ultrasonic treatment time is over, the mixed melt is poured into a graphite mold preheated at 300° C., and cooled with liquid nitrogen to obtain the final nano-titanium boride reinforced aluminum matrix composite material. 2. The method for preparing a titanium boride reinforced aluminum-based composite material based on ultrasound and mechanical stirring according to claim 1, wherein one end of the ultrasonic radiation rod is connected to an ultrasonic transducer, and the other end is immersed in the graphite crucible. In the mixed melt; the transducer is electrically connected with the ultrasonic power source. 3 . The method for preparing a titanium boride reinforced aluminum-based composite material based on ultrasonic and mechanical stirring according to claim 2 , wherein the aluminum alloy ingot is a 2Al4 aluminum alloy. 4 . 4. The method for preparing a titanium boride reinforced aluminum-based composite material based on ultrasonic and mechanical stirring according to claim 2 or 3, characterized in that: in step S3, the time for controlling the addition of the reaction salt and the cosolvent is 15 to 25 s, and in step S3 When the reaction salt and the cosolvent are added, a stirrer is used for mechanical stirring, the stirring speed is 150 rpm, and the stirring time is 30 min. 5. The method for preparing a titanium boride reinforced aluminum-based composite material based on ultrasonic and mechanical stirring according to claim 4, wherein the graphite crucible is provided with a thermocouple for measuring the temperature of the mixed melt. The signal output end is electrically connected with the data collector, and the data collector is connected in communication with the computer terminal.

Images