Fe-containing intermetallic compound and preparation method thereof

Abstract

The invention belongs to the technical field of non-ferrous metal smelting, and particularly relates to a Fe-containing intermetallic compound and a preparation method thereof. The intermetallic compound comprises elements Al, Fe, M and Si, M is one or more of transition metal elements, the crystal structure of the intermetallic compound is a body-centered cube or a face-centered cube, the size of the intermetallic compound is 50-1000 microns, and the Young modulus value is 80-200 GPa. The preparation method comprises the following steps: proportioning: weighing the raw materials according to the mass ratio, removing surface scales, and ultrasonically cleaning for later use; smelting: putting the prepared raw materials into a crucible, and putting the crucible into a smelting furnace for smelting; heat preservation is conducted, specifically, after alloy smelting is completed, heat preservation is conducted for a certain time at a certain temperature, and intermetallic compounds are fully formed and grow; and cooling: cooling the alloy at a certain cooling rate to obtain the intermetallic compound. And the obtained Fe-containing intermetallic compound has excellent high-temperature strength and toughness, compact structure and excellent mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal smelting, and particularly relates to an Fe-containing intermetallic compound and a preparation method thereof. Background Art

[0002] Iron-containing intermetallic compounds have promising applications in aerospace, high-temperature environments, and highly corrosive and oxidizing environments due to their low density, high strength, and excellent high-temperature performance, as well as corrosion and oxidation resistance. However, currently available iron-containing compounds often suffer from poor high-temperature performance and insufficient toughness, limiting their application.

[0003] Chinese invention patent CN1403607A discloses a method for preparing FeAl compounds by combustion synthesis and melting. This method is simple and low-cost, but the resulting FeAl binary intermetallic compound has low high-temperature resistance and poor toughness, which cannot meet application requirements. Chinese invention patent CN113817977A discloses a method for preparing a core-shell Al-Fe intermetallic compound. This method obtains Al-Fe intermetallic compound powder particles by reacting nano-alumina powder with an iron salt solution. The intermetallic compound powder particles obtained by this process have uniform composition and good bonding properties, but due to its powder properties, its application conditions are limited.

[0004] To address the shortcomings of existing Fe-containing intermetallic compounds, which currently suffer from insufficient high-temperature strength and toughness, the present invention utilizes a vacuum melting method to prepare multi-component Fe-containing intermetallic compounds. This method yields Fe-containing intermetallic compounds with high hardness, excellent high-temperature mechanical properties, and good toughness, significantly broadening the application range of Fe-containing intermetallic compounds. Summary of the Invention

[0005] In response to the current problems of low high-temperature mechanical properties and insufficient toughness of Fe-containing intermetallic compounds, the present invention proposes an Fe-containing intermetallic compound and a preparation method to improve the high-temperature performance and toughness of the Fe-containing intermetallic compound and expand the application range of the Fe-containing intermetallic compound.

[0006] In order to solve the above-mentioned technical problems, this application provides the following technical solutions:

[0007] The present invention provides an Fe-containing intermetallic compound. The Fe-containing intermetallic compound comprises Al, Fe, M and Si by weight; the mass ratio of Al, Fe, M and Si is 5-8:1:1-10:1-12; and M is selected from one or more transition metal elements.

[0008] Preferably, the M is selected from one or more of Mn, Cr, Co, Mo, Co, Be, W, Ni, V, Ti and B. The Fe-containing intermetallic compound has a body-centered cubic or face-centered cubic crystal structure, a size of 50-1000 μm, a Young's modulus of 80-200 GPa, and a fracture toughness of 1.2-2.2 MPa·m 1 / 2 .

[0009] The present invention also provides a method for preparing the above-mentioned Fe-containing intermetallic compound, comprising the following steps:

[0010] S1: Weigh the raw materials, pre-treat them and place them into a crucible to obtain the ingredients to be smelted;

[0011] S2: melting the ingredients to be smelted in a smelting furnace under a protective atmosphere and keeping the temperature high so that the intermetallic compounds are fully formed and grown to obtain a molding material;

[0012] S3: Cooling the molding material to obtain the Fe-containing intermetallic compound; during cooling, gradually immersing the molding material in a cooling medium in a vertical direction, with a cooling rate of 200-600K / s and a temperature gradient of 10-60k / mm.

[0013] Preferably, the raw materials include pure metals and master alloys; the master alloys are selected from blocks or metal powders.

[0014] Preferably, in step S1, the pretreatment method is to remove the surface oxide scale, ultrasonically clean, and dry for standby use.

[0015] Preferably, in step S2, the smelting temperature is 690-1000° C. and the smelting time is 20-80 min.

[0016] Preferably, in step S2, the heating method for smelting is induction heating or arc heating, and the heating power is 0.3-1.5Kw.

[0017] Preferably, the protective atmosphere is argon or nitrogen.

[0018] Preferably, in step S2, the furnace is vacuumed before the alloy is heated, and the vacuum degree is higher than 5×10 -3 Pa.

[0019] Preferably, in step S2, the insulation temperature is 630-750° C., and the insulation time is 30-120 min.

[0020] Preferably, a low melting point liquid alloy is used as the cooling medium and is gradually immersed from top to bottom along the vertical direction.

[0021] The technical solution of the present invention has the following advantages over the prior art:

[0022] The Fe-containing intermetallic compound and preparation method disclosed in the present invention prepare the multi-component Fe-containing intermetallic compound by vacuum melting, effectively solving the problems of low high-temperature performance and poor toughness of existing Fe-containing intermetallic compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a microstructure diagram of the Fe-containing intermetallic compound prepared in Example 1 of the present invention;

[0024] Figure 2 This is a microstructure diagram of the Fe-containing intermetallic compound prepared in Example 2 of the present invention;

[0025] Figure 3 This is a microstructure diagram of the Fe-containing intermetallic compound prepared in Example 3 of the present invention;

[0026] Figure 4 This is a microstructure diagram of the Fe-containing intermetallic compound prepared in Example 4 of the present invention;

[0027] Figure 5 This is the microstructure diagram of the Fe-containing intermetallic compound prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0029] Example 1

[0030] This example prepares an Fe-containing intermetallic compound and describes its preparation method. The specific steps are as follows:

[0031] (1) According to the ratio of Wt% (Al): Wt% (Fe): Wt% (M): Wt% (Si) = 5:1:10:1, a block material is weighed, where M is Mn and Cr, and the surface oxide scale is removed, ultrasonic cleaning is performed, and drying is performed for later use;

[0032] (2) Melting: The raw materials are placed in a crucible, and the crucible is placed in a melting furnace for melting. The melting temperature is 690°C, the heating method is electromagnetic induction heating, the heating power is 0.3Kw, and the vacuum degree in the furnace during the heating process is 4×10 -3 Pa, after the vacuum degree in the furnace reaches the requirement, high-purity Ar gas is filled in for protection;

[0033] (3) Insulation: After the alloy is smelted, it is kept at 630°C for 30 minutes to allow the intermetallic compounds to fully form and grow;

[0034] (4) Cooling: After the alloy is kept warm, it is gradually immersed in Ga+In eutectic alloy from top to bottom. The temperature gradient during the cooling process is 10k / mm. Figure 1 As shown, its crystal structure is body-centered cubic. The Young's modulus is 80GPa after nanoindentation test. The fracture toughness test (test standard: GB / T4161-2007) shows that the fracture toughness of the Fe-containing compound is 2.2MPa·m 1 / 2 .

[0035] Example 2

[0036] This example prepares an Fe-containing intermetallic compound and describes its preparation method. The specific steps are as follows:

[0037] (1) According to the ratio of Wt% (Al): Wt% (Fe): Wt% (M): Wt% (Si) = 8:1:1:6, a bulk raw material is weighed, where M is Mn, Mo and V, the surface oxide scale is removed, ultrasonic cleaning is performed, and drying is performed for later use;

[0038] (2) Melting: The raw materials are placed in a crucible, and the crucible is placed in a melting furnace for melting. The melting temperature is 730°C, and the heating method is induction heating or arc heating. The heating power is 1.2Kw. During the heating process, the vacuum degree in the furnace is higher than 5×10 - 4 Pa, after the vacuum degree in the furnace reaches the requirement, high-purity N2 gas is filled in for protection;

[0039] (3) Insulation: After the alloy is smelted, it is kept at 750°C for 120 minutes to allow the intermetallic compounds to fully form and grow;

[0040] (4) Cooling: After the alloy is kept warm, it is gradually immersed in Ga+In eutectic alloy from top to bottom. The temperature gradient during the cooling process is 40k / mm. Figure 2 As shown, its crystal structure is body-centered cubic. The Young's modulus is 200GPa after nanoindentation test. The fracture toughness test (test standard: GB / T4161-2007) shows that the fracture toughness of the Fe-containing compound is 1.2MPa·m 1 / 2 .

[0041] Example 3

[0042] This example prepares an Fe-containing intermetallic compound and describes its preparation method. The specific steps are as follows:

[0043] (1) Weighing bulk raw materials according to the ratio of Wt% (Al): Wt% (Fe): Wt% (M): Wt% (Si) = 6:1:2:12, where M is Co, Be, and Ni, removing the surface oxide scale, ultrasonically cleaning, and drying for later use;

[0044] (2) Melting: The raw materials are placed in a crucible, and the crucible is placed in a melting furnace for melting. The melting temperature is 920°C, the heating method is arc heating, the heating power is 1.5Kw, and the vacuum degree in the furnace during the heating process is 3×10 -3 Pa, after the vacuum degree in the furnace reaches the requirement, high-purity Ar gas is filled in for protection;

[0045] (3) Holding: After the alloy is smelted, it is kept at 690°C for 75 minutes to allow the intermetallic compounds to fully form and grow;

[0046] (4) Cooling: After the alloy is kept warm, it is gradually immersed in Ga+In eutectic alloy from top to bottom. The temperature gradient during the cooling process is 60k / mm. Figure 3 As shown, its crystal structure is face-centered cubic. The Young's modulus is 140GPa after nanoindentation test. The fracture toughness of the Fe-containing compound is 1.4MPa·m 1 / 2 .

[0047] Example 4

[0048] This example prepares an Fe-containing intermetallic compound and describes its preparation method. The specific steps are as follows:

[0049] (1) Weighing bulk raw materials according to Wt% (Al): Wt% (Fe): Wt% (M): Wt% (Si) = 7:1:5.5:7, where M is Mn, W, and B, removing surface oxide scale, ultrasonically cleaning, and drying for later use;

[0050] (2) Melting: The raw materials are placed in a crucible, and the crucible is placed in a melting furnace for melting. The melting temperature is 1000°C, the heating method is induction heating or arc heating, the heating power is 0.9Kw, and the vacuum degree in the furnace during the heating process is 2×10 -3 Pa, after the vacuum degree in the furnace reaches the requirement, high-purity N2 gas is filled in for protection;

[0051] (3) Holding: After the alloy is smelted, it is kept at 660°C for 55 minutes to allow the intermetallic compounds to fully form and grow;

[0052] (4) Cooling: After the alloy is kept warm, it is gradually immersed in Ga+In eutectic alloy from top to bottom. The temperature gradient during the cooling process is 55k / mm.

[0053] This embodiment prepares α-AlFeCoBeNiSi structure as Figure 4 As shown, its crystal structure is face-centered cubic. The Young's modulus is 170GPa after nanoindentation test. The fracture toughness of the Fe-containing compound is 1.65MPa·m after fracture toughness test (test standard: GB / T4161-2007). 1 / 2 .

[0054] Example 5

[0055] This example prepares an Fe-containing intermetallic compound and describes its preparation method. The specific steps are as follows:

[0056] (1) Weighing bulk raw materials according to Wt% (Al): Wt% (Fe): Wt% (M): Wt% (Si) = 6.5:1:7.5:4, where M is Mo, W, and Ti, removing surface oxide scale, ultrasonically cleaning, and drying for later use;

[0057] (2) Melting: The raw materials are placed in a crucible, and the crucible is placed in a melting furnace for melting. The melting temperature is 850°C, and the heating method is induction heating or arc heating. The heating power is 0.7Kw. The vacuum degree in the furnace during the heating process is higher than 6×10 - 4 Pa, after the vacuum degree in the furnace reaches the requirement, high-purity Ar gas is filled in for protection;

[0058] (3) Holding: After the alloy is smelted, it is kept at 720°C for 95 minutes to allow the intermetallic compounds to fully form and grow;

[0059] (4) Cooling: After the alloy is kept warm, it is gradually immersed in Ga+In eutectic alloy from top to bottom. The temperature gradient during the cooling process is 35k / mm.

[0060] This embodiment prepares α-AlFeMoWTiSi structure such as Figure 5 As shown, its crystal structure is face-centered cubic. The Young's modulus is 80-200GPa after nanoindentation test. The fracture toughness of the Fe-containing compound is 1.2-2.2MPa·m after fracture toughness test (test standard: GB / T4161-2007). 1 / 2 .

[0061] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. An Fe-containing intermetallic compound, characterized in that In terms of weight fraction, the Fe-containing intermetallic compound comprises Al, Fe, M and Si; the mass ratio of Al, Fe, M and Si is 5-8:1:1-10:1-12; and M is selected from two or more transition metal elements.

2. The Fe-containing intermetallic compound according to claim 1, characterized in that The M is selected from one or more of Mn, Cr, Co, Mo, Co, Be, W, Ni, V, Ti and B.

3. A method for preparing the Fe-containing intermetallic compound according to claim 1 or 2, characterized in that: The steps include: S1: weigh the raw materials, put them into a crucible after pretreatment, and obtain the ingredients to be smelted; S2: melting the ingredients to be melted in a melting furnace under a protective atmosphere, and keeping the temperature to obtain a molding material; S3: Cooling the molding material to obtain the Fe-containing intermetallic compound; during cooling, a low melting point liquid alloy is gradually immersed in a cooling medium along a vertical direction, a cooling rate is 200-600K / S, and a temperature gradient is 10-60k / mm.

4. The preparation method according to claim 3, characterized in that: The raw materials include a master alloy; the master alloy is selected from a block or a metal powder.

5. The preparation method according to claim 3, characterized in that: In step S1, the pretreatment method is to remove the surface oxide scale, ultrasonically clean, and dry for standby use.

6. The preparation method according to claim 3, characterized in that: In the step S2, the smelting temperature is 690-1000° C. and the smelting time is 20-80 min.

7. The preparation method according to claim 3, characterized in that: In the step S2, the heating method for smelting is induction heating or arc heating, and the heating power is 0.3-1.5Kw.

8. The preparation method according to claim 3, characterized in that: The protective atmosphere is argon or nitrogen.

9. The preparation method according to claim 3, characterized in that: In step S2, the insulation temperature is 630-750° C. and the insulation time is 30-120 min.

10. The preparation method according to claim 3, characterized in that: The cooling medium is selected from gallium-indium alloy.

Images