A Fe x Mn 80-x Co 10 Cr 10 New material and preparation method of high entropy alloy nanoparticle reinforced 304L stainless steel

Abstract

The present invention proposes a Fe x Mn 80‑x Co 10 Cr 10 High entropy alloy nanoparticle reinforced 304L stainless steel new material and preparation method, Fe x Mn 80‑x Co 10 Cr 10 High entropy alloy and 304L stainless steel powder are directly melted by coaxial laser in argon atmosphere via dual-path powder feeding to obtain Fe x Mn 80‑x Co 10 Cr 10 Nanoparticle-reinforced 304L-based new material has a typical "fish scale" structure, with austenite columnar crystals filling it, and a small amount of ferrite dispersed between the crystals. x Mn 80‑x Co 10 Cr 10 It is distributed in the austenite and has a coherent or semi-coherent relationship with its interface, which greatly improves the strength and plasticity of the material.

Description

Technical Field

[0001] The invention relates to a high entropy alloy nanoparticle reinforced 304L stainless steel new material and a preparation method thereof, belonging to the field of new materials. Background Art

[0002] 304L stainless steel has good machinability, weldability and good strength and plasticity. It is widely used in aerospace, nuclear power, ships, medical equipment, energy chemical industry and food. Studies have found that its performance can be further improved by adding reinforcing phases. At present, the commonly used reinforcing phases are mostly ceramic particles, such as WC, TiC, NbC, Al2O3, etc. Although ceramic particles can significantly improve strength, they often cause plasticity to decrease and are prone to failure under complex working conditions such as high loads and impacts. In addition, the industrial production cost of these ceramic particles is high. Finding a new reinforcing phase to simultaneously improve strength, plasticity and is crucial for 304L stainless steel. In addition, these ceramic particle reinforced 304L stainless steel materials are usually obtained through powder metallurgy or in-situ self-generation, and the formed parts need to undergo secondary "subtractive" processing, which is not only not conducive to the forming of complex structural parts, but also complicated the process and added costs. Therefore, it is of great engineering and economic significance to explore a method that integrates material preparation and forming process. Summary of the invention

[0003] In view of the above-mentioned needs, the present invention proposes a new high-entropy alloy nano-enhanced 304L stainless steel material and a preparation method, which not only improves the strength but also increases the plasticity.

[0004] To achieve the above object, the present invention first proposes a Fe x Mn 80-x Co 10 Cr 10 High entropy alloy nanoparticle reinforced 304L stainless steel new material, the material matrix is ​​304L stainless steel, the reinforcement phase is Fe x Mn 80-x Co 10 Cr 10 High entropy alloy particles, Fe x Mn 80-x Co 10 Cr 10 The nano-Fe nanoparticles are distributed in the matrix at nanoscale, and the structure presents a typical "fish scale" shape, with austenite columnar crystals filling it. x Mn 80-x Co 10 Cr 10 It is distributed in austenite and has a coherent or semi-coherent relationship with its interface.

[0005] Preferably, the Fe x Mn 80-x Co10 Cr 10 For high entropy alloys, the value of x is 35~50.

[0006] The present invention also proposes a Fe x Mn 80-x Co 10 Cr 10 The preparation method of high entropy alloy nanoparticle reinforced 304L stainless steel new material mainly involves Fe x Mn 80-x Co 10 Cr 10 High entropy alloy and 304L stainless steel powder are fed through dual channels and directly melted by coaxial laser in argon atmosphere to obtain nano-Fe x Mn 80-x Co 10 Cr 10 High entropy alloy reinforced 304L new material.

[0007] Preferably, Fe x Mn 80-x Co 10 Cr 10 The total mass ratio of high entropy alloy to 304L stainless steel powder is 1%~10%.

[0008] Preferably, Fe x Mn 80-x Co 10 Cr 10 The particle size of high entropy alloy powder is 53~105 μm, and the particle size of 304L stainless steel powder is 53~105 μm.

[0009] Preferably, the coaxial laser direct melting forming process, the laser power is 1800~2200 W, Fe x Mn 80-x Co 10 Cr 10 The feeding rate of high entropy alloy powder is 0.05~1 cm 3 / min, the feeding rate of 304L stainless steel powder is 2~10 cm 3 / min, laser scanning speed 700~2000 mm / min.

[0010] The advantage of the present invention is that the Fe x Mn 80-x Co 10 Cr 10 High-entropy alloy nanoparticles reinforced 304L stainless steel new material can simultaneously enhance material strength and plasticity without sacrificing corrosion resistance. x Mn 80-x Co 10Cr 10 The new material of high-entropy alloy nanoparticle reinforced 304L stainless steel can be directly obtained through the method of dual-path powder feeding coaxial laser direct melting forming, while near-net-shaped parts can be formed without prior powder mixing and subsequent subtractive processing, which greatly simplifies the process and shortens the development cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The Fe prepared in Example 1 of the present invention x Mn 80-x Co 10 Cr 10 High entropy alloy nanoparticles reinforced 304L stainless steel new material microstructure;

[0012] Figure 2 The Fe prepared in Example 1 of the present invention x Mn 80-x Co 10 Cr 10 Ferrite phase in the microstructure of 304L stainless steel new material reinforced by high entropy alloy nanoparticles. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described below.

[0014] Example 1

[0015] This embodiment relates to a Fe x Mn 80-x Co 10 Cr 10 High entropy alloy nanoparticle reinforced 304L stainless steel new material, x value is 40, its preparation process is as follows:

[0016] 1) Take Fe separately 40 Mn 40 Co 10 Cr 10 The 304L stainless steel powder is placed in a dual-path powder feeding coaxial laser direct melting forming storage container. 40 Mn 40 Co 10 Cr 10 5% of the mass of 304L stainless steel powder, Fe x Mn 80-x Co 10 Cr 10 The particle size of high entropy alloy powder is 55~100 μm, and the particle size of 304L stainless steel powder is 60~105 μm;

[0017] 2) Coaxial laser direct melting forming in argon atmosphere to obtain Fe40 Mn 40 Co 10 Cr 10 Nano-enhanced 304L stainless steel new material, laser power 2000 W, Fe x Mn 80-x Co 10 Cr 10 The feeding rate of high entropy alloy powder is 0.5cm 3 / min, the feeding rate of 304L stainless steel powder is 5cm 3 / min, laser scanning speed 1000 mm / min.

[0018] Prepared Fe x Mn 80-x Co 10 Cr 10 Nanoparticle reinforced 304L stainless steel new material structure as shown in the attached Figure 1 , showing a typical "fish scale" shape, with austenite columnar crystals distributed in it ( Figure 1 ), a small amount of ferrite is dispersed between the grains ( Figure 2 ), Fe x Mn 80- x Co 10 Cr 10 The high entropy alloy is distributed in the crystal at the nanoscale, and its interface with the matrix is ​​coherent. The material has a yield strength of 481 MPa, a tensile strength of 917 MPa, and an elongation of 69%. x Mn 80-x Co 10 Cr 10 Nanoparticle-reinforced 304L stainless steel (yield strength 260 MPa, tensile strength 670 MPa, elongation 65%) increased by 85%, 37%, and 6%, respectively.

[0019] Comparative Example 1

[0020] The preparation method of Comparative Example 1 is generally the same as that of Example 1, except that x is 20.

[0021] There is almost no ferrite in the prepared material structure, the material has a yield strength of 239 MPa, a tensile strength of 582 MPa, and an elongation of 51%.

[0022] Comparative Example 2

[0023] The preparation method of Comparative Example 2 is generally the same as that of Example 1, except that the powder is not directly melted by a dual-path powder feeding coaxial laser, but is pre-mixed and then melted by a selective laser.

[0024] The prepared material has a large number of unfused defects and a large area of ​​ferrite phase. The material has a yield strength of 209 MPa, a tensile strength of 511 MPa, and an elongation of 41%.

[0025] Comparative Example 3

[0026] The preparation method of Comparative Example 3 is the same as that of Example 1, except that in step 1) Fe 40 Mn 40 Co 10 Cr 10 0.5% of the mass of 304L stainless steel powder

[0027] The yield strength of the prepared material is 250 MPa, the tensile strength is 669 MPa, and the elongation is 51%. x Mn 80-x Co 10 Cr 10 Particle enhancement has not improved.

[0028] Comparative Example 4

[0029] The preparation method of Comparative Example 4 is the same as that of Example 1, except that in step 1) Fe x Mn 80-x Co 10 Cr 10 The particle size of high entropy alloy powder is 20~50 μm.

[0030] No nano-Fe was found in the prepared material structure. x Mn 80-x Co 10 Cr 10 The material yield strength is 252 MPa, the tensile strength is 667 MPa, and the elongation is 56%. x Mn 80-x Co 10 Cr 10 Particle enhancement has not improved.

[0031] Comparative Example 5

[0032] The preparation method of Comparative Example 5 is generally the same as that of Example 1, except that the particle size of the 304L stainless steel powder in step 1) is 110-150 μm.

[0033] The prepared material structure Fe x Mn 80-x Co 10 Cr 10 The particle size is significantly increased, up to micron level, the material yield strength is 269 MPa, the tensile strength is 675 MPa, and the elongation is 56%, which is much better than that of Fe-free x Mn80-x Co 10 Cr 10 The particle enhancement is not obvious.

[0034] Comparative Example 6

[0035] The preparation method of Comparative Example 6 is generally the same as that of Example 1, except that the laser power in step 2) is 1000 W.

[0036] The prepared material has a large number of unfused defects, the material yield strength is 205 MPa, the tensile strength is 501 MPa, and the elongation is 42%.

[0037] Comparative Example 7

[0038] The preparation method of Comparative Example 7 is generally the same as that of Example 1, except that the laser power in step 2) is 3000 W.

[0039] The prepared material does not contain nano-Fe x Mn 80-x Co 10 Cr 10 Particles appear, the material yield strength is 259 MPa, the tensile strength is 665 MPa, and the elongation is 53%, which is higher than that of Fe-free x Mn 80-x Co 10 Cr 10 The particle enhancement is not obvious.

[0040] Comparative Example 8

[0041] The preparation method of Comparative Example 8 is the same as that of Example 1, except that in step 2) Fe x Mn 80-x Co 10 Cr 10 High entropy alloy powder feeding rate 0.02 cm 3 / min.

[0042] The prepared material does not contain nano-Fe x Mn 80-x Co 10 Cr 10 Particles appear, the material yield strength is 263 MPa, the tensile strength is 655 MPa, and the elongation is 56%, which is higher than that of Fe-free x Mn 80-x Co 10 Cr 10 The particle enhancement is not obvious.

[0043] Comparative Example 9

[0044] The preparation method of Comparative Example 9 is the same as that of Example 1, except that the feeding rate of 304L stainless steel powder in step 2) is 15 cm 3 / min.

[0045] The prepared material does not contain nano-Fe x Mn 80-x Co 10 Cr 10 Particles appear, the material yield strength is 257 MPa, the tensile strength is 645 MPa, and the elongation is 67%, which is higher than that of Fe-free x Mn 80-x Co 10 Cr 10 The particle enhancement is not obvious.

[0046] For the convenience of comparison, the material properties of the implementation example and the comparative example are shown in Table 1;

[0047] Table 1 Comparison of material properties

[0048]

[0049] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A kind of Fe x Mn 80-x Co 10 Cr 10 High entropy alloy nanoparticle reinforced 304L stainless steel new material, the matrix is ​​304L stainless steel, the reinforcement phase is Fe x Mn 80-x Co 10 Cr 10 High entropy alloy particles, Fe x Mn 80-x Co 10 Cr 10 The matrix is ​​distributed at nanometer scale, and the organization presents a typical "fish scale" shape, with austenite columnar crystals filling it, and a small amount of ferrite dispersed between the crystals. x Mn 80-x Co 10 Cr 10 Nanoparticles are distributed in austenite and have a coherent or semi-coherent relationship with its interface, with x ranging from 35 to 50.

2. A kind of Fe x Mn 80-x Co 10 Cr 10 The preparation method of high entropy alloy nanoparticle reinforced 304L stainless steel new material mainly involves Fe x Mn 80-x Co 10 Cr 10 High entropy alloy and 304L stainless steel powder are fed through dual channels and directly melted by coaxial laser in argon atmosphere to obtain nano-Fe x Mn 80-x Co 10 Cr 10 High entropy alloy reinforced 304L new material, x value is 35~50.

3. A method for preparing the new material according to claim 2, characterized in that Fe x Mn 80-x Co 10 Cr 10 The high entropy alloy is 1% to 10% of the total mass of the 304L stainless steel powder.

4. A method for preparing the new material according to claim 2, characterized in that Fe x Mn 80-x Co 10 Cr 10 The particle size of high entropy alloy powder is 53~105 μm, and the particle size of 304L stainless steel powder is 53~105 μm.

5. A method for preparing the new material according to claim 2, characterized in that The coaxial laser direct melting forming process is a laser power of 1800~2200 W, Fe x Mn 80-x Co 10 Cr 10 The feeding rate of high entropy alloy powder is 0.05~1 cm 3 / min, the feeding rate of 304L stainless steel powder is 2~10 cm 3 / min, laser scanning speed 700~2000 mm / m.

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