Preparation process of fast-reaction TiAl intermetallic compound reinforced aluminum matrix composite

Abstract

The application relates to the technical field of material preparation, in particular to a preparation process of a fast-reaction TiAl intermetallic compound reinforced aluminum matrix composite material, which comprises the following steps: proportionally weighing titanium powder and aluminum powder, grinding and fully mixing the two in a mortar, and placing the mixture in a tablet press to be compressed into a mixed powder briquette for standby; then proportionally weighing aluminum ingots and placing the aluminum ingots in a graphite crucible, and placing the graphite crucible in a high-temperature furnace to be fully melted to obtain a melt; next, the mixed powder briquette is quickly pressed into the melt, and the melt is quickly stirred, so that the titanium in the melt reacts with the aluminum liquid quickly, TiAl intermetallic compounds are generated in situ in the aluminum liquid, a large amount of heat is generated, and a composite melt is obtained; finally, the composite melt is quickly pressure-poured to obtain the TiAl / Al matrix composite material. The TiAl / Al matrix composite material is prepared by utilizing reaction heat, the reaction speed is high, the synthesis process is simple, the preparation cost is reduced, and the mechanical properties of the prepared composite material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material preparation, and particularly to a preparation process of a rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material. BACKGROUND

[0002] Aluminum matrix composite materials have high specific strength, specific modulus, good stability and economy, and have been widely used in aerospace, transportation, automobile, chemical industry, construction and many other fields. Among them, TiAl intermetallic compounds are concerned and deeply researched due to their low density, high specific strength, high elastic modulus, good creep resistance and oxidation resistance. In recent years, with the rapid development of manned aerospace, aircraft, high-speed rail, automobile and other industries, TiAl / Al matrix composite materials with higher specific strength and specific modulus are continuously developed, which have broad development prospects.

[0003] In the traditional preparation method of aluminum matrix composite materials, powder metallurgy is the first commonly used method, which has superior material performance. However, the equipment of this method is complex, the production efficiency is low, and due to the limitation of the process conditions and process principles required by the process itself, it is difficult to prepare parts with complex shape and large size, thus limiting its development and application. With the development of technology, hot rolling method has become the main preparation process of aluminum matrix composite materials, such as the patents with patent number CN103305725A, patent number CN104561854A and patent number CN112157268B. However, it can be seen that the products prepared by these patents have single structure, and the operation process needs to be carried out at high temperature, which increases the cost of preparation, and its economic benefit needs to be further improved. At present, casting process is the most widely used preparation process for aluminum alloy and its composite materials. However, due to the high reactivity of aluminum liquid, it is easy to react with many materials and cause corrosion of the material, leading to casting difficulty. In addition, the reaction between aluminum liquid and titanium produces a large amount of heat, which is easy to cause spitting phenomenon, leading to difficult control of the preparation process, so there is no report on the preparation of TiAl / Al matrix composite materials by casting process.

[0004] The purpose of the present application is to overcome the shortcomings of the existing process, and to prepare TiAl / Al matrix composite materials by in-situ self-generation at low temperature using reaction heat. SUMMARY

[0005] In view of the problems existing in the above-mentioned existing field, the purpose of the present application is to provide a preparation process of a rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material which is simple to operate, cost-saving, high in preparation efficiency and good in preparation effect. In order to achieve the purpose of the present application, the following technical solutions are adopted:

[0006] A preparation process of a fast-reaction TiAl intermetallic compound reinforced aluminum matrix composite material, comprising the following steps:

[0007] (1) Pretreatment: titanium powder and aluminum powder are weighed according to the proportion, ground and mixed in a mortar, and then placed in a tablet press to be pressed into a mixed powder briquette for later use;

[0008] (2) Preparation of melt: aluminum ingots are weighed according to the proportion, placed in a graphite crucible, and fully melted in a high-temperature furnace to obtain a melt;

[0009] (3) Melting: the mixed powder briquette in step (1) is quickly pressed into the melt obtained in step (2), and rapidly stirred to make titanium in the melt react with aluminum liquid to generate TiAl intermetallic compounds in situ and generate a large amount of heat, thereby obtaining a composite melt;

[0010] (4) Post-treatment: the composite melt obtained in step (3) is rapidly pressure-cast to obtain a TiAl / Al matrix composite material.

[0011] Preferably, the mass ratio of titanium powder to aluminum powder in the mixed powder briquette in step (1) is (3-8):(2-7).

[0012] Preferably, the pressure of the tabletting in step (1) is not more than 10 MPa.

[0013] Preferably, the temperature of the melt in step (2) is 750-850℃.

[0014] Preferably, the mass of the mixed powder briquette in step (3) is not more than 30% of the mass of the melt.

[0015] Preferably, the crucible containing the melt in the melting process in step (3) is placed on a vibration table.

[0016] Preferably, the stirring time in step (3) is 3-30s.

[0017] Preferably, before pressure casting in step (4), the composite melt is quickly transferred to a high-temperature furnace for heat preservation, and the heat preservation temperature of the high-temperature furnace is 800-850℃, and the heat preservation time is 20-30min.

[0018] Preferably, the pressure casting in step (4) comprises the following steps:

[0019] 1) Place the mold in a muffle furnace and preheat at 300-350℃;

[0020] 2) Place the preheated mold in step 1) on a vibration table, quickly cast the composite melt into the mold, and place the pressure head;

[0021] 3) Put the mold into the press machine as a whole, slowly press in, stop for about 5-10s after the composite melt seeps out the gap of the mold, then continue to slowly press down, repeat several times, until the pressure indicator reaches 1MPa;

[0022] 4) Take the mold from the press machine, cool in air after opening the mold, and obtain the TiAl / Al-based composite material with less defects.

[0023] Preferably, the surface of the mold is coated with an anti-adhesion coating, and the anti-adhesion coating is one of a zinc oxide anti-adhesion coating or a boron nitride anti-adhesion coating.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] (1) The present application realizes the preparation of TiAl / Al composite material by one-step method through traditional casting process in-situ self-generation, has fast reaction speed, simple synthesis process, fully utilizes the reaction heat generated by the fast reaction of titanium and aluminum liquid, reduces the preparation cost, and fully uniformly disperses the generated TiAl intermetallic compound in the aluminum alloy, has good wettability, and the average particle size is in nanometer level, the titanium aluminum intermetallic compound is thermodynamically stable, improves the mechanical properties of the TiAl / Al composite material, and widens the application field of the composite material.

[0026] (2) In the preparation process, the introduction form of titanium element is improved, the smooth progress of the preparation process is ensured, and the waste of resources is reduced; the titanium element is added in the form of powder, which is beneficial to the adjustment of the proportion, and is added into the melt after being pressed into a block, and the reaction heat is combined to generate TiAl intermetallic compound with aluminum liquid corrosion resistance, which is beneficial to the preparation of the composite material. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a flowchart of the preparation process of the present application of a fast-reaction TiAl intermetallic compound reinforced aluminum-based composite material.

[0028] Figure 2 It is a flowchart of pressure pouring in the present application.

[0029] Figure 3 It is an XRD spectrum of the sample prepared in each embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1

[0032] Figure 1 This is a schematic flow diagram of the preparation process of a rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material according to the present invention, and in conjunction with... Figure 2 As can be seen from this, the preparation process of a rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material of the present invention includes the following steps:

[0033] Step S1: Pretreatment: Weigh titanium powder and aluminum powder according to the ratio, grind and mix them thoroughly in a mortar, and then place them in a tablet press to compress the mixed powder into a block for later use. In this step, the tableting pressure is 10 MPa, and the mass ratio of titanium powder to aluminum powder in the mixed powder block is 3:7.

[0034] Step S2: Preparation of the melt: Weigh aluminum ingots according to the proportion, put them into a graphite crucible, and place them in a pit-type high-temperature furnace to fully melt them to obtain a melt at a temperature of 750℃.

[0035] Step S3: Melting: Place the crucible containing the melt on a vibrating table, and quickly press the mixed powder block from step S1 into the melt obtained in step S2 (in this step, the mass of the mixed powder block is 30% of the mass of the melt). Stir rapidly for 3 seconds to allow the titanium in the melt to react quickly with the aluminum liquid, generating TiAl intermetallic compounds in situ in the aluminum liquid and producing a large amount of heat (the melt quickly turns bright yellow), thus obtaining a composite melt.

[0036] Step S4: After slag removal and degassing of the composite melt obtained in Step S3 (using C2Cl6 for degassing), rapid pressure casting is performed to obtain the TiAl / Al-based composite material. In this step, pressure casting includes the following steps (e.g., Figure 2 ):

[0037] Step S401: Place the mold (cast iron mold) in a muffle furnace and preheat it to 300°C; wherein, the surface of the mold is coated with an anti-sticking coating, namely zinc oxide anti-sticking coating.

[0038] Step S402: Place the preheated mold from step S401 onto the vibration table, quickly pour the composite melt into the mold, and place the pressure head in;

[0039] Step S403: Put the mold into the press machine as a whole, slowly press in, stop for about 5s after the composite melt seeps out of the gap of the mold, continue to slowly press down, repeat the above steps for several times, until the pressure indicator reaches 1MPa;

[0040] Step S404: Take the mold off the press machine, cool in the air after opening the mold, obtain the TiAl / Al-based composite material with less defects, and test the related performance of the material. Specific embodiment 2

[0042] Figure 1 The flowchart of the preparation process of the TiAl intermetallic compound reinforced aluminum matrix composite material is shown in the figure, and the preparation process of the TiAl intermetallic compound reinforced aluminum matrix composite material is described in detail as follows. Figure 2 As can be seen from the figure, the preparation process of the TiAl intermetallic compound reinforced aluminum matrix composite material includes the following steps:

[0043] Step S1: Pretreatment: weigh titanium powder and aluminum powder according to the proportion, grind and mix them in a mortar, and then put them into a tablet press to press into a mixed powder briquette for later use. In this step, the pressure for tablet pressing is 9MPa, and the mass ratio of titanium powder to aluminum powder in the mixed powder briquette is 8:2.

[0044] Step S2: Preparation of melt: weigh aluminum ingot according to the proportion, put it into a graphite crucible, and put it into a pit-type high-temperature furnace for full melting to obtain a melt with a temperature of 850℃.

[0045] Step S3: Melting: put the crucible containing the melt on a vibration table, quickly press the mixed powder briquette in step S1 into the melt obtained in step S2 (in this step, the mass of the mixed powder briquette is 28% of the mass of the melt), and stir quickly for 30s to make the titanium in the melt react quickly with the aluminum liquid to generate TiAl intermetallic compound in situ and generate a large amount of heat (the melt quickly turns bright yellow), and obtain a composite melt.

[0046] Step S4: After the composite melt obtained in step S3 is deslagged and degassed (using C2Cl6), pressure casting is carried out quickly to obtain a TiAl / Al-based composite material. In this step, the pressure casting includes the following steps (as shown in Figure 2 ):

[0047] Step S401: Put the mold into the muffle furnace and preheat it at 350℃; wherein the surface of the mold is coated with an anti-adhesion coating, i.e. a boron nitride anti-adhesion coating;

[0048] Step S402: Put the preheated mold in step S401 on a vibration table, quickly pour the composite melt into the mold, and put it into the press head;

[0049] Step S403: Put the mold into the press machine as a whole, slowly press in, stop for about 10s after the composite melt seeps out of the gap of the mold, continue to slowly press down, repeat the above steps for several times, until the pressure indicator reaches 1MPa;

[0050] Step S404: Take the mold off the press machine, cool in the air after opening the mold, obtain the TiAl / Al-based composite material with less defects, and test the related performance of the material. Specific embodiment 3

[0052] Figure 1 The flowchart of the preparation process of the TiAl intermetallic compound reinforced aluminum matrix composite material is shown in the figure, and the preparation process of the TiAl intermetallic compound reinforced aluminum matrix composite material is described in detail as follows. Figure 2 As can be seen from the figure, the preparation process of the TiAl intermetallic compound reinforced aluminum matrix composite material includes the following steps:

[0053] Step S1: Pretreatment: weigh titanium powder and aluminum powder according to the proportion, grind and mix them in a mortar, and then put them into a tablet press to press into a mixed powder briquette for later use. In this step, the pressure for tablet pressing is 9MPa, and the mass ratio of titanium powder to aluminum powder in the mixed powder briquette is 4:6.

[0054] Step S2: Preparation of melt: weigh aluminum ingot according to the proportion, put it into a graphite crucible, and put it into a pit-type high-temperature furnace for full melting to obtain a melt with a temperature of 800℃.

[0055] Step S3: Melting: put the crucible containing the melt on a vibration table, quickly press the mixed powder briquette in step S1 into the melt obtained in step S2 (in this step, the mass of the mixed powder briquette is 26% of the mass of the melt), and stir quickly for 10s to make the titanium in the melt react quickly with the aluminum liquid to generate TiAl intermetallic compound in situ in the aluminum liquid and generate a large amount of heat (the melt quickly turns bright yellow), and obtain a composite melt.

[0056] Step S4: quickly transfer the composite melt obtained in step S3 to a high-temperature furnace at 800℃ for heat preservation for 30min, and then perform pressure pouring after slagging and degassing (using C2Cl6 for degassing) to obtain a TiAl / Al-based composite material. In this step, the pressure pouring includes the following steps (as shown in Figure 2 ):

[0057] Step S401: Put the mold into the muffle furnace and preheat at 320℃; wherein the surface of the mold is coated with an anti-adhesion coating, i.e. a zinc oxide anti-adhesion coating;

[0058] Step S402: Put the preheated mold in step S401 on a vibration table, quickly pour the composite melt into the mold, and put it into the press head;

[0059] Step S403: Place the entire mold into the press and press it in slowly. Stop for about 8 seconds after the composite melt seeps out of the mold gap, and then continue to press down slowly. Repeat this process several times until the pressure gauge reading reaches 1MPa.

[0060] Step S404: Remove the mold from the press, open the mold and cool it in the air to obtain a TiAl / Al-based composite material with fewer defects, and test its relevant properties. Specific Implementation Example 4

[0062] Figure 1 This is a schematic flow diagram of the preparation process of a rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material according to the present invention, and in conjunction with... Figure 2 As can be seen from this, the preparation process of a rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material of the present invention includes the following steps:

[0063] Step S1: Pretreatment: Weigh titanium powder and aluminum powder according to the ratio, grind and mix them thoroughly in a mortar, and then place them in a tablet press to compress the mixed powder into a block for later use. In this step, the tableting pressure is 10 MPa, and the mass ratio of titanium powder to aluminum powder in the mixed powder block is 5:5.

[0064] Step S2: Preparation of melt: Weigh aluminum ingots according to the proportion, put them into a graphite crucible, and place them in a pit-type high-temperature furnace to fully melt them to obtain a melt at a temperature of 830℃.

[0065] Step S3: Melting: Place the crucible containing the melt on a vibrating table, and quickly press the mixed powder block from step S1 into the melt obtained in step S2 (in this step, the mass of the mixed powder block is 25% of the mass of the melt). Stir rapidly for 15 seconds to allow the titanium in the melt to react quickly with the aluminum liquid, generating TiAl intermetallic compounds in situ in the aluminum liquid and producing a large amount of heat (the melt quickly turns bright yellow), thus obtaining a composite melt.

[0066] Step S4: The composite melt obtained in Step S3 is rapidly transferred to a high-temperature furnace at 850℃ and held for 20 minutes. After slag removal and degassing (using C2Cl6 for degassing), pressure casting is performed to obtain the TiAl / Al-based composite material. In this step, pressure casting includes the following steps (such as...). Figure 2 ):

[0067] Step S401: Place the mold in a muffle furnace and preheat it to 300°C; wherein, the surface of the mold is coated with an anti-adhesion coating, namely boron nitride anti-adhesion coating.

[0068] Step S402: Place the preheated mold from step S401 onto the vibration table, quickly pour the composite melt into the mold, and place the pressure head in;

[0069] Step S403: Put the mold into the press machine as a whole, slowly press in, stop for about 6s after the composite melt seeps out of the mold gap, then continue to slowly press down, repeat the above steps for several times, until the pressure indicator reaches 1MPa;

[0070] Step S404: Take the mold off the press machine, cool in air after opening the mold, obtain the TiAl / Al-based composite material with less defects, and test the related performance.

[0071] Figure 3 From the XRD spectrum of the sample prepared in the embodiments of the present application, it can be seen that the TiAl / Al-based composite material is prepared by using the traditional casting process in-situ self-generation method, through the rapid in-situ synthesis process, at low temperature, using the reaction heat, the reaction speed is fast, the synthesis process is simple, the preparation cost is reduced, the TiAl intermetallic compound generated by the reaction is fully and uniformly dispersed in the aluminum alloy, the wettability is good, the average particle size is in nanometer level, the titanium aluminum intermetallic compound is thermodynamically stable, the mechanical properties of the TiAl / Al composite material are improved, and the application field of the composite material is widened.

[0072] In addition, in the pretreatment process, the titanium powder and the aluminum powder are mixed in the form of powder, then pressed into a mixed powder briquette, and the mixed powder briquette is quickly pressed into the melt under stirring, the mixed powder briquette is not dispersed in the process, and the exothermic material spraying is avoided, that is, in the preparation process of the present application, by improving the introduction form of titanium element, the smooth progress of the preparation process is ensured, and the waste of resources is reduced; the titanium element is mixed and added in the form of powder, which is beneficial to the adjustment of the proportion, and after being pressed into a briquette, it is added into the melt, and combined with the reaction heat, the TiAl intermetallic compound with aluminum liquid corrosion resistance is generated, which is beneficial to the preparation of the composite material

[0073] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can understand and think of the transformation or replacement within the technical range disclosed by the present application, which should be covered in the inclusive scope of the present application, therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A process for preparing a rapidly reacting TiAl intermetallic compound reinforced aluminum-based composite material, characterized in that: Includes the following steps: (1) Pretreatment: Weigh titanium powder and aluminum powder according to the proportion, grind them in a mortar and mix them thoroughly, then place them in a tablet press and press them into mixed powder blocks for later use; (2) Preparation of melt: Weigh aluminum ingots according to the proportion, put them into a graphite crucible, and place them in a high-temperature furnace to fully melt them to obtain melt; (3) Melting: The mixed powder block in step (1) is quickly pressed into the melt obtained in step (2), and stirred rapidly so that the titanium in the melt reacts rapidly with the aluminum liquid, and TiAl intermetallic compound is generated in situ in the aluminum liquid and a large amount of heat is generated to obtain a composite melt. (4) Post-processing: The composite melt obtained in step (3) is rapidly pressure cast to obtain TiAl / Al-based composite material; Before pressure casting in step (4), the composite melt is quickly transferred to a high-temperature furnace for heat preservation, and the heat preservation temperature of the high-temperature furnace is 800-850℃ and the heat preservation time is 20-30 min. The pressure casting described in step (4) includes the following steps: 1) Place the mold in a muffle furnace and preheat it to 300-350℃; 2) Place the preheated mold from step 1) on the vibrating table, quickly pour the composite melt into the mold, and place the pressure head in; 3) Place the entire mold into the press and press it in slowly. Stop for 5-10 seconds after the composite melt seeps out of the mold gap, and then continue to press down slowly. Repeat this process several times until the pressure gauge reading reaches 1MPa. 4) Remove the mold from the press, open the mold, and cool it in air to obtain a TiAl / Al-based composite material with fewer defects; The mass ratio of titanium powder and aluminum powder in the mixed powder briquettes in step (1) is (3-8):(2-7).

2. The preparation process of the rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material as described in claim 1, characterized in that: The pressure of the tablet compression in step (1) shall not exceed 10 MPa.

3. The preparation process of the rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material as described in claim 1, characterized in that: The temperature of the melt in step (2) is 750-850℃.

4. The preparation process of the rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material as described in claim 1, characterized in that: The mass of the mixed powder briquettes in step (3) shall not exceed 30% of the mass of the melt.

5. The preparation process of the fast-reaction TiAl intermetallic compound reinforced aluminum matrix composite material as described in claim 1, characterized in that: In step (3), the melting process involves placing the crucible containing the melt on a vibrating table.

6. The preparation process of the rapid reaction TiAl intermetallic compound reinforced aluminum matrix composite material as described in claim 1, characterized in that: The stirring time in step (3) is 3-30 seconds.

7. The preparation process of the fast-reaction TiAl intermetallic compound reinforced aluminum matrix composite material as described in claim 1, characterized in that: The surface of the mold is coated with an anti-adhesion coating, which is either a zinc oxide anti-adhesion coating or a boron nitride anti-adhesion coating.

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