A method of producing a metal material and a low-activation ferritic / martensitic steel

Abstract

The disclosure provides a preparation method of a metal material and a low-activation ferrite / martensite steel. The preparation method adopts an additive manufacturing process, comprising: performing forming treatment on raw material powder by using a laser to obtain a formed sample; and performing heat treatment on the formed sample to obtain a metal material with a microstructure including oxides; wherein, during the forming treatment, the oxygen content in the printing cabin is controlled to be 300-2000 ppm. The chemical composition of the low-activation ferrite / martensite steel includes, in terms of mass percentage, Cr: 8.5%-9.5%, W: 0.8%-1.2%, Mn: 0.3%-0.6%, V: 0.1%-0.4%, Si: 0.1%-0.2%, Ti: 0.15%-0.75%, Al: 0.1%-0.5%, Y: 0.05%-04%, and C: 0.05%-02%.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of component design and preparation of metal alloys, and more particularly, to a preparation method of a metal material and a low-activation ferritic / martensitic steel. BACKGROUND

[0002] Nuclear energy is a recognized clean energy with the largest reserves, and the realization of controlled nuclear fusion is one of the important strategic plans for energy development of each country, and the material used in fusion reactors is one of the main limitations of commercialization of controlled nuclear fusion. The low-activation ferritic / martensitic steel (RAFM) has advantages in terms of radiation swelling resistance, thermal expansion coefficient, high-temperature mechanical properties, and the like, and compared with vanadium alloy, SiC and other materials, the preparation process is mature and easy to process, and the RAFM has become the preferred material for the current domestic and foreign fusion reactor cladding materials and first wall / deflector.

[0003] The radiation resistance and high-temperature mechanical properties of the fusion reactor material are the focus, and the main idea of enhancing the performance of the low-activation steel is to control the content of Ti to be 0.16%-0.28%, the content of C to be 0.04%-0.07%, and Ti:C = 3-4:1 through alloy design, so that the low-activation steel can mainly precipitate MX phase (M = Ti, V, X = C) in the matrix after rolling-quenching / annealing-tempering process, and avoid precipitating M23C6 phase which has relatively high coarsening speed and relatively low thermal stability. At present, some studies show that the strengthening effect of MX phase on the radiation resistance and high-temperature mechanical properties is not as good as that of the dispersed nanometer oxide, so there are still problems in the above alloy design. The conventional method of introducing oxide second phase is to mix oxide powder with metal powder and form through mechanical alloying. This method has a complex process, high cost, low operability, is easy to introduce impurities, and the quality of the finally generated oxide is closely related to the mixing quality of the nanometer oxide particles in the mixing process, which is not suitable for large-scale industrial production.

[0004] Therefore, in order to realize the application of the low-activation steel in the fusion reactor cladding material, it is necessary to further generate dispersed nanometer oxides with better performance in the matrix, and new alloy design and new manufacturing process ideas are needed. SUMMARY

[0005] Therefore, in order to realize the application of the low-activation steel in the fusion reactor cladding material, it is necessary to further generate dispersed nanometer oxides with better performance in the matrix, and new alloy design and new manufacturing process ideas are needed.

[0006] According to one aspect of the present disclosure, a method for preparing a metal material is provided, which employs an additive manufacturing process, comprising: performing a forming treatment on a raw material powder by means of a laser to obtain a formed sample; and performing a heat treatment on the formed sample to obtain a metal material with a microstructure including oxides; wherein, during the forming treatment, the oxygen content in the printing cabin is controlled to be 300-2000 ppm.

[0007] According to an embodiment of the present disclosure, the step of performing a forming treatment on a raw material powder by means of a laser further comprises: proportioning raw materials according to the composition of the metal material and smelting, obtaining the raw material powder by means of a vacuum atomization powdering technology; and designing the shape of the metal material, and introducing the shape into an additive manufacturing device after slicing processing.

[0008] According to an embodiment of the present disclosure, the particle size of the raw material powder is 15-53 μm, the D50 is 36 μm, the sphericity is >90%, the flowability is <20 s, and the loose bulk density is >4.1 g / cm3.

[0009] According to an embodiment of the present disclosure, in the step of performing a forming treatment on a raw material powder by means of a laser, the parameters of the additive manufacturing process are: the laser power is 180-220 W, the scanning speed is 700-1000 mm / s, the scanning interval is 80-120 μm, the layer thickness is 30 μm, the rotation angle is 67°, and the scanning strategy is stripe mode.

[0010] According to an embodiment of the present disclosure, the chemical components of the raw material powder include C, V and active elements, wherein the active elements are used to combine with O in the printing cabin to form the oxides.

[0011] According to an embodiment of the present disclosure, the metal material with a microstructure including oxides further includes carbides, and the metal material is a low-activation ferrite / martensite steel which is collectively strengthened by the oxides and carbides.

[0012] According to an embodiment of the present disclosure, the chemical components of the carbides include Ti, V and C, and the chemical components of the oxides include Ti, V and O.

[0013] According to an embodiment of the present disclosure, the active elements include at least one of Ti, Al and Y.

[0014] According to an embodiment of the present disclosure, the chemical components of the metal material satisfy:

[0015] A×[O]+B×[C]=[M1]+[V]

[0016] In the formula, the range of A is [1.5, 2]; the range of B is [3, 4]; [O], [C], [M1] and [V] represent the mass percentages of the corresponding chemical components, respectively, wherein [M1] is the sum of the mass percentages of active elements.

[0017] According to an embodiment of the present disclosure, in the step of performing heat treatment on the shaped sample, the heat treatment comprises annealing and tempering.

[0018] According to an embodiment of the present disclosure, the temperature of the annealing is 1000-1050℃, and the time of the annealing is 20-30min.

[0019] According to an embodiment of the present disclosure, the temperature of the tempering is 600-700℃, and the time of the tempering is 20-120min.

[0020] Another aspect of the present disclosure provides a low-activation ferritic / martensitic steel co-strengthened by oxides and carbides, the chemical components of the low-activation ferritic / martensitic steel comprising Cr, W, Mn, V, Si, Ti, C and Fe, wherein: the mass percentage of the Cr in the low-activation ferritic / martensitic steel is [8.5, 9.5]wt%, the mass percentage of the W in the low-activation ferritic / martensitic steel is [0.8, 1.2]wt%, the mass percentage of the Mn in the low-activation ferritic / martensitic steel is [0.3, 0.6]wt%, the mass percentage of the V in the low-activation ferritic / martensitic steel is [0.1, 0.4]wt%, the mass percentage of the Si in the low-activation ferritic / martensitic steel is [0.1, 0.2]wt%, the mass percentage of the Ti in the low-activation ferritic / martensitic steel is [0.15, 0.75]wt%, and the mass percentage of the C in the low-activation ferritic / martensitic steel is [0.05, 0.2]wt%.

[0021] According to an embodiment of the present disclosure, the low-activation ferritic / martensitic steel has a microstructure comprising ferrite, martensite, carbides and oxides.

[0022] According to an embodiment of the present disclosure, the chemical components of the carbides comprise Ti, V and C, and the size of the carbides is 10-50nm; the chemical components of the oxides comprise Ti, V and O, and the size of the oxides is 30-100nm.

[0023] According to an embodiment of the present disclosure, the chemical components of the low-activation ferritic / martensitic steel further comprise active metals, and the oxides are formed by the active metals and oxygen.

[0024] According to an embodiment of the present disclosure, the active metals comprise at least one of Al and Y.

[0025] According to an embodiment of the present disclosure, the mass percentage of the Al in the low-activation ferrite / martensite steel is [0.1, 0.5]wt%; the mass percentage of the Y in the low-activation ferrite / martensite steel is [0.05, 0.4]wt%.

[0026] According to an embodiment of the present disclosure, the chemical components of the low-activation ferrite / martensite steel satisfy:

[0027] A x [O] + B x [C] = [Ti] + [V] + [M2]

[0028] In the formula, the range of A is [1.5, 2]; the range of B is [3, 4]; [O], [C], [Ti], [V], and [M2] respectively represent the mass percentage of the corresponding chemical components, wherein [M2] is the sum of the mass percentages of active metals.

[0029] From the above technical solution, the metal material preparation method and the low-activation ferrite / martensite steel provided by the present disclosure have the following beneficial effects:

[0030] 1. The metal material preparation method provided by the present disclosure uses additive manufacturing technology to prepare an oxide dispersion strengthened metal material. Compared with traditional mechanical alloying methods, additive manufacturing technology is more economical and efficient, and can manufacture complex structural parts, and is very suitable for manufacturing nuclear fusion reactor blanket materials with complex structures.

[0031] 2. The metal material preparation method provided by the present disclosure does not require powder pretreatment, and by controlling the printing parameters and oxygen content, the size and distribution of in-situ oxides can be better regulated.

[0032] 3. The metal material preparation method provided by the present disclosure uses laser selective melting technology to prepare metal materials, which do not require mechanical processing, and already have a large number of dislocation nucleation sites and many solid-solution oxygen clusters inside, which provides the possibility for subsequent heat treatment to improve the structure, increase the precipitated phase, and improve the performance.

[0033] 4. The low-activation ferrite / martensite steel provided by the present disclosure can obtain a low-activation ferrite / martensite steel that is jointly strengthened by precipitated nanocarbide and in-situ generated nanooxide, while avoiding the generation of M23C6 phase, and optimizing the structure and performance of the low-activation steel. BRIEF DESCRIPTION OF DRAWINGS

[0034] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0035] Figure 1A flow chart of a method of preparing a metal material in embodiments of the present disclosure is schematically shown;

[0036] Figure 2 A TEM map of a low-activation ferritic / martensitic steel in Comparative Example 1 of the present disclosure is schematically shown;

[0037] Figure 3 An EBSD map of a low-activation ferritic / martensitic steel in Comparative Example 2 of the present disclosure is schematically shown;

[0038] Figure 4 A TEM map of a low-activation ferritic / martensitic steel in Comparative Example 2 of the present disclosure is schematically shown;

[0039] Figure 5 An EBSD map of a low-activation ferritic / martensitic steel in Example 1 of the present disclosure is schematically shown; and

[0040] Figure 6 A TEM map of a low-activation ferritic / martensitic steel in Example 1 of the present disclosure is schematically shown.

[0041] The reference numerals in the drawings are: 1 - ferrite, 2 - martensite, 3 - oxide, 4 - M23C6 phase, 5 - MX phase. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood, however, that the description which follows is merely exemplary and is not intended to limit the scope of the present disclosure. In the following detailed description of the embodiments of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it would be apparent to one skilled in the art that the embodiments of the present disclosure can be practiced without these specific details. In other instances, well-known structures and techniques have not been described in detail in order to avoid obscuring aspects of the present disclosure.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the term "includes" and tautological expressions thereof, such as "including," "includes," "include," "contains," "containing," and so forth, shall not be taken to exclude

[0044] In the case of using expressions such as "at least one of A, B or C", etc., it is generally intended that the inclusion of at least one of A or B or C, etc. be understood to imply any one of these items individually, A alone, B alone, C alone, any two of the items, A and B together, A and C together, B and C together, or all three A, B, and C together, etc. It will be understood by those within the art that the term "first", "second", etc. are used herein only to describe one of the features. Thus, the use of the term "first" does not imply that the feature so described is superior to or preferred over the other features. In the claims, means-plus-function, step-plus-function, and / or other integrated formats can be used for enacting embodiments of the present disclosure. Accordingly, it will be understood that the terms "means for" and "step for" are used herein only to describe the function of the features described. Thus, the use of the term "means for" does not limit the scope of the claims to only those embodiments described herein. In addition, it will be understood that the features of the embodiments of the present disclosure, as described herein, can be combined with other features of the present disclosure, as described herein, unless otherwise indicated.

[0045] Figure 1 A flow chart of a method for preparing a metal material is schematically shown in the embodiments of the present disclosure.

[0046] As shown in Figure 1 The embodiments of the present disclosure provide a method for preparing a metal material, which adopts an additive manufacturing process, comprising:

[0047] Step 1: forming a sample by using laser on raw material powder, wherein, during the forming process, the oxygen content in the printing cabin is controlled to be 300-2000 ppm. The method for controlling the oxygen content is to use an argon bottle mixed with 500-3000 ppm oxygen, which is constantly introduced into the printing cabin to provide a stable source of oxygen elements.

[0048] Step 2: heat treating the sample to obtain a metal material with microstructure including oxides. Suitable post-heat treatment can eliminate stress during the forming process, improve the structure, increase the precipitated phase, and improve the performance.

[0049] It should be noted that the additive manufacturing process, i.e. laser selective melting technology, controls the oxygen content during the 3D printing process to combine active elements with oxygen elements to generate oxides in situ in the matrix. This is an efficient and economical method for preparing oxide dispersion strengthened (ODS) metal materials with free shape. Compared with the traditional mechanical alloying method, the additive manufacturing technology is more economical and efficient, and can manufacture complex structural parts, which is very suitable for manufacturing nuclear fusion reactor cladding materials with complex structure.

[0050] In the embodiments of the present disclosure, before the step of forming a sample by using laser on raw material powder in step 1, the method further comprises:

[0051] Step 10: proportioning raw materials according to the composition of the metal material and smelting to obtain the raw material powder by using a vacuum atomization powdering technology;

[0052] Step 20: design the shape of the metal material, slice the shape and introduce it into the additive manufacturing equipment. The shape can be designed by CAD software and sliced to be introduced into the 3D printing equipment.

[0053] Optionally, in the embodiments of the present disclosure, the particle size of the raw powder is 15-53 μm, the D50 is 36 μm, the sphericity is >90%, the flowability is <20 s, and the loose bulk density is >4.1 g / cm 3 .

[0054] In the embodiments of the present disclosure, in the step of forming the raw powder by laser, the parameters of the additive manufacturing process are: the laser power is 180-220 W, the scanning speed is 700-1000 mm / s, the scanning interval is 80-120 μm, the layer thickness is 30 μm, the rotation angle is 67°, and the scanning strategy is stripe mode.

[0055] Optionally, in the embodiments of the present disclosure, the chemical components of the raw powder include C, V and active elements, wherein the active elements are used to combine with O in the printing cabin to form the oxides. Any active element that can easily combine with oxygen can be used to prepare oxide dispersion strengthened (ODS) metal materials by the preparation method, and the present disclosure does not limit this.

[0056] Optionally, in the embodiments of the present disclosure, the metal material including oxides also includes carbides, and the metal material is a low-activation ferrite / martensite steel strengthened by the oxides and carbides, wherein the carbides are MX phases (TiC and VC).

[0057] In the embodiments of the present disclosure, the chemical components of the carbides include Ti, V and C; and the chemical components of the oxides include Ti, V and O.

[0058] In the embodiments of the present disclosure, the active elements include at least one of Ti, Al and Y.

[0059] In the embodiments of the present disclosure, the chemical components of the metal material satisfy:

[0060] A×[O]+B×[C]=[M1]+[V]

[0061] In the formula: the range of A is [1.5, 2]; the range of B is [3, 4]; [O], [C], [M1] and [V] respectively represent the mass percentage of the corresponding chemical components in the metal material, wherein [M1] is the sum of the mass percentages of the active elements in the metal material. [O] is oxygen introduced in the preparation process, most of which is in the oxides, and a small part is solid-solved in the matrix.

[0062] In embodiments of the present disclosure, in the step of heat treating the shaped sample in step 2, the heat treatment comprises annealing and tempering, and the shaped sample needs to be cut from the substrate before heat treatment.

[0063] Optionally, in embodiments of the present disclosure, the annealing temperature is 1000-1050℃, and the annealing time is 20-30min.

[0064] Optionally, in embodiments of the present disclosure, the tempering temperature is 600-700℃, and the tempering time is 20-120min.

[0065] Embodiments of the present disclosure provide a metal material preparation method, which is suitable for metal materials containing active elements that are easy to combine with oxygen elements in alloy components. Without powder pretreatment, by using additive manufacturing technology, the oxygen content is relatively stable between 300ppm-2000ppm, and suitable laser parameters are selected to prepare oxide dispersion strengthened (ODS) metal materials. The laser parameters can control the cooling speed during material forming, and the oxygen content can control the number of oxides in the matrix. By controlling the printing parameters and oxygen content, the size and distribution of in-situ oxides can be better regulated. In addition, by using laser selective melting technology to prepare metal materials, mechanical processing is not required, and a large number of dislocation nucleation sites and many solid-solution oxygen clusters exist inside, which can be precipitated through heat treatment to improve the organization, increase the precipitated phase, and improve the performance.

[0066] Based on the above Figure 1 The metal material preparation method shown in the above embodiment of the present disclosure also provides a low-activation ferrite / martensite steel co-strengthened by oxides and carbides, which is prepared by the above method. The chemical composition of the low-activation ferrite / martensite steel includes Cr, W, Mn, V, Si, Ti, C, and Fe. The mass percentage of Cr in the low-activation ferrite / martensite steel is [8.5, 9.5]wt%, the mass percentage of W in the low-activation ferrite / martensite steel is [0.8, 1.2]wt%, the mass percentage of Mn in the low-activation ferrite / martensite steel is [0.3, 0.6]wt%, the mass percentage of V in the low-activation ferrite / martensite steel is [0.1, 0.4]wt%, the mass percentage of Si in the low-activation ferrite / martensite steel is [0.1, 0.2]wt%, the mass percentage of Ti in the low-activation ferrite / martensite steel is [0.15, 0.75]wt%, and the mass percentage of C in the low-activation ferrite / martensite steel is [0.05, 0.2]wt%.

[0067] In embodiments of the present disclosure, the low-activation ferritic / martensitic steel has a microstructure including ferrite, martensite, carbide and oxide. The microstructure of the low-activation ferritic / martensitic steel is dominated by ferrite, with some martensite, strengthened by both nanometer carbide and in-situ nanometer oxide, wherein the carbide is MX phase (TiC and VC).

[0068] Optionally, in embodiments of the present disclosure, the chemical composition of the carbide includes Ti, V, C, and the size of the carbide is 10-50 nm; the chemical composition of the oxide includes Ti, V, O, and the size of the oxide is 30-100 nm.

[0069] In embodiments of the present disclosure, the chemical composition of the low-activation ferritic / martensitic steel further includes an active metal, and the oxide is formed by the active metal and oxygen.

[0070] In embodiments of the present disclosure, the active metal includes at least one of Al and Y.

[0071] In embodiments of the present disclosure, the mass percentage of Al in the low-activation ferritic / martensitic steel is [0.1, 0.5] wt%, and the mass percentage of Y in the low-activation ferritic / martensitic steel is [0.05, 0.4] wt%.

[0072] In embodiments of the present disclosure, the chemical composition of the low-activation ferritic / martensitic steel satisfies:

[0073] A x [O] + B x [C] = [Ti] + [V] + [M2]

[0074] In the formula, the range of A is [1.5, 2], the range of B is [3, 4], and [O], [C], [Ti], [V] and [M2] represent the mass percentages of the corresponding chemical components in the low-activation ferritic / martensitic steel, wherein [M2] is the sum of the mass percentages of the active metals in the low-activation ferritic / martensitic steel.

[0075] It should be noted that when designing the alloy composition of the low-activation ferritic / martensitic steel, the following factors are considered:

[0076] On the one hand, the content ratio of Ti, V and C is precisely controlled during the powder making process, so as to form dispersed MX phase (TiC and VC) instead of M23C6 phase (rich in Cr and Fe); on the other hand, Ti element is additionally added on the basis of the original ratio, and combined with O element provided in the manufacturing process to generate in-situ oxide. The control of Ti content is the most important, which ensures the generation of in-situ oxide, avoids the precipitation of M23C6 phase, increases the precipitation of MX phase, and avoids the precipitation of Laves phase.

[0077] The metal material preparation method provided by the present disclosure utilizes a laser selective melting technology, and by controlling the oxygen content in the 3D printing process, the active element is combined with the oxygen element to generate oxides in situ in the matrix, so that the ODS metal material is obtained, which has the advantages of high efficiency, economy and free shape preparation.

[0078] The low-activation ferrite / martensite steel provided by the present disclosure not only can regulate the microstructure, but also can generate a second phase of dispersed nanometer oxides in situ in the manufacturing process and control the size and density of the second phase, which can avoid the generation of M23C6 phase on one hand and achieve the effects of precipitating nanometer MX phase (carbide) and generating dispersed nanometer oxides in situ on the other hand, so that the low-activation ferrite / martensite steel with the common strengthening of precipitated nanometer carbide and in-situ generated nanometer oxides is obtained, and the microstructure and performance of the low-activation steel are optimized.

[0079] The performance of the low-activation ferrite / martensite steel provided by the present disclosure will be described in detail below in combination with examples and related experiments.

[0080] Comparative Example 1

[0081] The element composition of the low-activation martensite / ferrite steel in the present comparative example is as follows in terms of mass percentage: Cr: 9%, W: 1%, Mn: 0.45%, V: 0.20%, Si: 0.15%, Ti: 0.2%, and C: 0.06%.

[0082] The preparation method of the low-activation martensite / ferrite steel in the present comparative example comprises:

[0083] (1) preparing an alloy material containing C, Cr, W, V, Si, Mn, Ti and Fe in the mass percentages;

[0084] (2) austenitizing the alloy material;

[0085] (3) isothermally transforming the austenitized alloy material into ferrite phase;

[0086] (4) after the isothermal ferrite phase transformation is completed, cooling.

[0087] The temperature of the isothermal ferrite phase transformation is 650-675℃, and the time is 2.5-4h; the temperature of the austenitization is 980-1080℃, and the time is more than 30min.

[0088] No additive manufacturing technology is used in Comparative Example 1. As shown in Figure 2 the microstructure matrix obtained in Comparative Example 1 is ferrite 1, and there is no M23C6 phase in the microstructure, and only MX phase 5 is used as the precipitated strengthening phase.

[0089] Comparative Example 2

[0090] The element composition of the low-activation martensite / ferrite steel of the present comparative example is, in mass percentage: Cr: 9.14%, W: 0.94%, Mn: 0.46%, V: 0.20%, Si: 0.16%, Ti: 0.12%, C: 0.056%.

[0091] The in-situ oxide generating low-activation martensite / ferrite steel of the present comparative example is prepared by the following process:

[0092] (1) The element raw materials of Fe, Cr, W, Mn, V, Ti, C, Si are melted according to the element formula by vacuum atomization powdering technology to obtain a powder suitable for additive manufacturing;

[0093] (2) The powder obtained in step (1) is shaped by additive manufacturing technology using slm280 equipment, and the scanned powder is rapidly solidified and melted according to the set path, wherein the laser parameters are: laser power: 200 W, scanning speed: 600 mm / s, scanning interval: 120 pm, layer thickness: 30 pm, rotation angle: 67°, scanning strategy is stripe mode, and the oxygen concentration in the printing cabin is controlled to be 500 ppm during the printing process;

[0094] (3) The sample obtained in step (2) is cut from the substrate;

[0095] (4) The sample obtained in step (3) is heat treated by annealing at 1050°C for 30 min and tempering at 750°C for 30 min.

[0096] As shown in FIG. 1, the microstructure of the sample in step (3) is characterized by a heterogeneous structure of fine and coarse grains, mainly ferrite 1 with a small amount of martensite 2 distributed therein, some 50 nm-200 nm oxide 3 particles in the matrix, and some 30 nm*200 nm rod-shaped M23C6 phase 4 distributed perpendicularly. In the heat-treated sample (4), the rod-shaped M23C6 phase disappears, some dispersed MX phase precipitates on the surface of the previously in-situ generated oxide particles, and visible M23C6 phase precipitates at the grain boundaries. Although the heat treatment increases the precipitated phase, this alloy composition cannot avoid the generation of M23C6 phase. Figures 3-4

[0097] Example 1

[0098] ​The elemental composition of the low-activation martensitic / ferritic steel in this embodiment, by mass percentage, is: Cr: 8.90%, W: 0.82%, Mn: 0.23%, V: 0.0021%, Si: 0.086%, Ti: 0.27%, C: 0.075%.

[0099] The low-activation martensitic / ferritic steel with in-situ oxide formation in this embodiment is prepared by the following process:

[0100] (1) Fe, Cr, W, Mn, V, Ti, C and Si elemental raw materials are smelted according to the elemental formula by vacuum atomization powder making technology to obtain powder suitable for additive manufacturing;

[0101] (2) The powder obtained in step (1) is formed using additive manufacturing technology and an SLM280 device. The laser rapidly solidifies and melts the powder it has scanned along a set path. The laser parameters are: laser power: 200W, scanning speed: 600mm / s, scanning distance: 120μm, layer thickness: 30μm, rotation angle: 67°, scanning strategy: stripe mode, and the oxygen concentration in the printing chamber is controlled to be 500ppm during the printing process.

[0102] (3) Cut the sample obtained in step (2) off the substrate;

[0103] (4) The sample obtained in step (3) is subjected to heat treatment at 1050℃ for 30 min and tempered at 750℃ for 60 min.

[0104] like Figures 5-6 As shown, the microstructure of the sample obtained in step (3) is as follows: the microstructure exhibits a heterogeneous structure with a mixture of fine and coarse grains, with ferrite 1 as the main component and some martensite 2 distributed within it. The content of martensite 2 is significantly higher than that of Comparative Example 2, indicating that the slight adjustment of the C element content has a significant effect on its microstructure. The matrix contains a large amount of MX phase 5 and in-situ generated oxide 3, with almost no Cr or Fe-rich M23C6 phase. The content of the second phase is much higher than that of Comparative Example 2, and the size is also smaller than that of Comparative Example 2. The size of MX phase 5 is 10-50 nm, and the size of oxide 3 is 30-100 nm, indicating that by controlling the content of Ti, O, and C, MX phase 5 and oxide 3 particles with a balanced distribution and small size appear in the matrix. The tensile test results of the sample in Example 1 are as follows: tensile strength 802 MPa, elongation 8%, which is better than Comparative Example 1 and Comparative Example 2.

[0105] Those skilled in the art can understand that the features recited in various embodiments and / or claims of the present disclosure can be combined and / or integrated in various combinations, even if such combinations or integrations are not expressly recited in the present disclosure. In particular, the features recited in various embodiments and / or claims of the present disclosure can be combined and / or integrated in various combinations without departing from the spirit and teachings of the present disclosure. All such combinations and / or integrations fall within the scope of the present disclosure.

[0106] The above describes embodiments of the present disclosure. However, these embodiments are merely for illustrative purposes, and are not intended to limit the scope of the present disclosure. Although each embodiment is described above separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for producing a metal material, characterized by, The preparation method adopts an additive manufacturing process for in-situ generating oxides in a matrix by controlling the content of oxygen in a printing process to combine active elements in raw material powder with oxygen elements, and the method comprises: performing forming treatment on the raw material powder by using a laser to obtain a formed sample; and performing heat treatment on the formed sample to obtain a metal material with a microstructure including oxides; wherein the content of oxygen in a printing cabin is controlled to be 300-2000 ppm during the forming treatment, the metal material is a low-activated ferrite / martensite steel with precipitated carbides and in-situ generated oxides for common strengthening, and the preparation method can avoid the generation of M23C6 phases, a chemical composition of the raw material powder includes C, V and active elements, wherein the active elements are used to combine with O in the printing cabin to form the oxides, and the active elements include at least one of Ti, Al and Y, a chemical composition of the metal material satisfies: A×[O]+B×[C]=[M1]+[V] wherein A ranges from [1.5, 2], B ranges from [3, 4], and [O], [C], [M1] and [V] represent mass percentages of corresponding chemical components, wherein [M1] is the sum of mass percentages of active elements.

2. The method of claim 1, wherein, The step of performing forming treatment on the raw material powder by using a laser further comprises: proportioning raw materials according to the composition of the metal material and smelting to obtain the raw material powder by using a vacuum atomization powdering technology; and designing a shape of the metal material, and introducing the shape into an additive manufacturing device after slicing processing.

3. The method of claim 2, wherein, The raw material powder has a particle size of 15-53 μm, a D50 of 36 μm, a sphericity of > 90%, a flowability of < 20 s, and a loose bulk density of > 4.1 g / cm3 3 .

4. The method of claim 1, wherein, In the step of performing forming treatment on the raw material powder by using a laser, parameters of the additive manufacturing process are as follows: a laser power is 180-220 W, a scanning speed is 700-1000 mm / s, a scanning interval is 80-120 μm, a layer thickness is 30 μm, a rotation angle is 67°, and a scanning strategy is stripe mode.

5. The method of claim 1, wherein, A chemical composition of the carbides includes Ti, V and C, and a chemical composition of the oxides includes Ti, V and O.

6. The method of claim 1, wherein, In the step of performing heat treatment on the formed sample, the heat treatment includes annealing and tempering.

7. The method of claim 6, wherein, A temperature of the annealing is 1000-1050 ℃, and a time of the annealing is 20-30 min.

8. The method of claim 6, wherein, A temperature of the tempering is 600-700 ℃, and a time of the tempering is 20-120 min.

9. A low-activated ferritic / martensitic steel co-reinforced with oxides and carbides, produced by the method according to any one of claims 1 to 8, characterized in that, A chemical composition of the low-activated ferrite / martensite steel includes Cr, W, Mn, V, Si, Ti, C and Fe, wherein: a mass percentage of the Cr in the low-activated ferrite / martensite steel is [8.5, 9.5] wt%, a mass percentage of the W in the low-activated ferrite / martensite steel is [0.8, 1.2] wt%, a mass percentage of the Mn in the low-activated ferrite / martensite steel is [0.3, 0.6] wt%, a mass percentage of the V in the low-activated ferrite / martensite steel is [0.1, 0.4] wt%, a mass percentage of the Si in the low-activated ferrite / martensite steel is [0.1, 0.2] wt%, and a mass percentage of the Ti in the low-activated ferrite / martensite steel is [0.1, 0.2] wt%. The Ti is in a mass percentage of [0.15, 0.75]wt% in the low-activation ferrite / martensite steel, The C is in a mass percentage of [0.05, 0.2]wt% in the low-activation ferrite / martensite steel, The chemical composition of the low-activation ferrite / martensite steel further comprises an active metal, the oxide is formed by the active metal and oxygen, and the active metal comprises at least one of Al and Y, The chemical composition of the low-activation ferrite / martensite steel satisfies: A×[O]+B×[C]=[Ti]+[V]+[M2] In the formula, A ranges from [1.5, 2]; B ranges from [3, 4]; [O], [C], [Ti], [V] and [M2] respectively represent the mass percentage of the corresponding chemical composition, wherein [M2] is the sum of the mass percentage of the active metal.

10. The low-activation ferritic / martensitic steel according to claim 9, characterized in that, The low-activation ferrite / martensite steel has a microstructure, and the microstructure comprises ferrite, martensite, carbide and oxide.

11. The low-activation ferrite / martensite steel according to claim 10, wherein: The chemical composition of the carbide comprises Ti, V and C, and the size of the carbide is 10-50nm; The chemical composition of the oxide comprises Ti, V and O, and the size of the oxide is 30-100nm.

12. The low-activation ferrite / martensite steel according to claim 9, wherein: The Al is in a mass percentage of [0.1, 0.5]wt% in the low-activation ferrite / martensite steel; The Y is in a mass percentage of [0.05, 0.4]wt% in the low-activation ferrite / martensite steel.

Images