阅读说明：本技术 一种高强韧ods钢的高通量制备与成分工艺优选方法 (High-flux preparation and component process optimization method of high-strength and high-toughness ODS steel ) 是由 罗晋如 何培 王长浩 邓林 张鹏程 于 2021-04-15 设计创作，主要内容包括：本发明公开一种高强韧ODS钢的高通量制备与成分工艺优选方法,包括以下步骤：S1：通过机器学习方法对现有的高通量成分进行筛选,确定出基体合金成分的优选范围；S2：在优选范围内选择需要制备样品的成分,通过雾化制粉法制备基体合金成分的预合金粉末；S3：将制备得到的预合金粉末与Y-2O-3粉末通过高能球磨机混合均匀制得球磨粉末；S4：对制备得到的球磨粉末进行包套抽气制备得到粉坯；S5：重复步骤S2-S4,选取不同成分进行制备,并制得不同成分下的ODS钢粉末包套样品；S6：将不同成分ODS钢粉末包套样品进行热等静压同步烧结,制得不同成分下的坯料；S7：将坯料样品切割成楔形板材,对楔形板材经过高温保温处理后进行单道次平轧,制备厚度相同的轧制板材。(The invention discloses a high-flux preparation and component process optimization method of high-toughness ODS steel, which comprises the following steps: s1: screening the existing high-flux components by a machine learning method to determine the optimal range of the components of the matrix alloy;s2: selecting components of a sample to be prepared in an optimal range, and preparing prealloy powder of matrix alloy components by an atomization powder preparation method; s3: mixing the prepared prealloyed powder with Y 2 O 3 Uniformly mixing the powder by a high-energy ball mill to prepare ball-milled powder; s4: performing sheath and air extraction on the prepared ball-milled powder to prepare a powder blank; s5: repeating the steps S2-S4, selecting different components for preparation, and preparing ODS steel powder sheath samples under different components; s6: carrying out hot isostatic pressing synchronous sintering on ODS steel powder sheath samples with different components to prepare blanks with different components; s7: and cutting the blank sample into a wedge-shaped plate, carrying out high-temperature heat preservation treatment on the wedge-shaped plate, and then carrying out single-pass flat rolling to prepare a rolled plate with the same thickness.)

1. A high-flux preparation and component process optimization method for high-strength and high-toughness ODS steel is characterized by comprising the following steps:

s1: screening the existing high-flux components by a machine learning method to determine the optimal range of the components of the matrix alloy;

s2: selecting components of a sample to be prepared in an optimal range, and preparing prealloy powder of matrix alloy components by an atomization powder preparation method;

s3: mixing the prepared prealloyed powder with Y₂O₃Uniformly mixing the powder by a high-energy ball mill to prepare ball-milled powder;

s4: performing sheath and air extraction on the prepared ball-milled powder to prepare a powder blank;

s5: repeating the steps S2-S4, selecting different components for preparation, and preparing ODS steel powder sheath samples under different components;

s6: carrying out hot isostatic pressing synchronous sintering on ODS steel powder sheath samples with different components to prepare blanks with different components;

s7: and cutting the blank sample into a wedge-shaped plate, carrying out high-temperature heat preservation treatment on the wedge-shaped plate, and carrying out single-pass flat rolling to prepare a rolled plate with the same thickness.

2. The high-throughput preparation and component process optimization method of the high-toughness ODS steel according to claim 1, wherein the optimization range in step S1 is obtained by a machine learning method based on BP neural network algorithm.

3. The method for high-throughput preparation and component process optimization of the high-toughness ODS steel according to claim 1, wherein the prealloyed powder in step S2 is prepared by vacuum induction melting and gas atomization powder preparation.

4. The high-throughput preparation and composition process preferable method for the high-toughness ODS steel according to claim 1, characterized in that the prealloyed powder is mixed with 0.3% high-purity Y2O3 powder in a glove box by weighing in step S3, transferred to a ball mill pot under the protection of argon atmosphere, and then the mixed powder is mechanically alloyed by a high-energy planetary ball mill.

5. The method for high-throughput preparation and component process optimization of the high-toughness ODS steel according to claim 4, wherein the ball-milling rotation speed in step S3 is 600rpm, the ball-milling time is 40h, and the ball-to-material ratio is 5: 1.

6. The method for preparing high-throughput ODS steel with high toughness and composition process optimization of claim 1, wherein in step S4, the covering and pumping process is performed on the powder after mechanical alloying, wherein the heating temperature is 400 ℃, the heat preservation time is 10h, and the vacuum degree is not less than 10^-1Pa。

7. The method for high-throughput preparation and component process optimization of the high-toughness ODS steel according to claim 1, wherein in step S6, hot isostatic pressing simultaneous sintering is performed on powder capsule samples of different components, the reaction temperature is 1150 ℃, the pressure is 150MPa, and the holding time is 2 h.

8. The high-throughput preparation and component process optimization method for the high-toughness ODS steel according to claim 1, wherein in step S7, the wedge-shaped plate is subjected to high-temperature heat preservation treatment in an air furnace before rolling, the reaction temperature is 1150 ℃, and the heat preservation time is 30 min.

9. The high-throughput preparation and component process optimization method for the high-toughness ODS steel according to claim 8, wherein the inclination of the wedge-shaped plate is 7-15 °, and the rolling strain rate is 1-10s^-1。

10. The high-throughput preparation and component process optimization method of the high-toughness ODS steel according to claim 8, characterized in that 0-70% of the deformation of the wedge-shaped plate is selected as a deformation zone, the plate grains in the deformation zone are detected, and the optimal matrix alloy component and deformation are obtained.

Technical Field

The invention relates to the field of high-flux steel preparation and process optimization, in particular to a high-flux preparation and component process optimization method for high-toughness ODS steel.

Background

China is actively developing advanced nuclear energy systems such as fourth generation fission reactors, accelerator driven subcritical systems (ADS), fusion reactors and the like. The development of these advanced nuclear power systems aims to further improve thermal efficiency while ensuring operational safety, and thus presents a significant challenge to the stability of the structure and performance of critical structural materials and components in the reactor under extreme service conditions of high temperature, irradiation, corrosion, and stress coupling. Oxide Dispersion Strengthened (ODS) steel is a new type of core structure material with a high density oxide dispersed phase inside the grains. The dispersed phases have excellent high-temperature stability, do not react with a matrix structure in a high-temperature environment, can effectively pin grain boundaries and dislocation, inhibit abnormal growth of crystal grains at high temperature, and improve the high-temperature stability and high-temperature mechanical properties of the material. The excellent properties of ODS steel derive from two main aspects: on one hand, the dispersed and fine nanoscale precipitated phase has high thermal stability, is beneficial to improving the high-temperature creep strength, and improving the highest service temperature, thereby bringing better economic effect. On the other hand, the irradiation defect is captured to play a role of a trap, and the neutron irradiation resistance is enhanced. Therefore, the excellent comprehensive performance of ODS steel in the environments of high-intensity neutron irradiation, high-concentration helium and nuclear reactor coolant liquid makes the ODS steel become a candidate material which is most hopefully applied to nuclear reactor cladding and fusion reactor structural cladding. A large number of researches show that component regulation and preparation process optimization are the two simplest and most effective methods for obtaining the ODS steel with excellent performance.

As the ODS steel develops, other trace elements begin to be added to the ODS steel. Wherein, the Y2O3 particle is an inert rare earth oxide, has stable physicochemical properties and larger neutron absorption cross section; even if the material is in service under high-temperature, long-time and stress environments, the movement of the pinning dislocation can still be stabilized, and the thermal stability of the high-temperature tissue of the material is improved. Meanwhile, the addition of a certain amount of Cr can further reduce the size of a nanometer precipitated phase and reduce the particle size distribution. However, the more the amount of Cr added, the better, the more the amount of Cr added is, and the more the amount of Cr added is, the more the material is, and the more the material is. The addition of Al greatly improves the corrosion resistance of the material by forming a dense surface oxide layer (Al2O3) but results in a decrease in strength. The addition of Ti can promote the precipitation of nano-oxides in the hot-setting forming and subsequent heat treatment of ODS steel. C in ODS steel tends to form a large amount of M23C6 carbides, resulting in creep failure and a sharp increase in ductile-to-brittle transition temperature (DBTT). W, Mo element is the main element forming Laves phase (Fe2W, Fe2Mo) in the high temperature time effect process, the too high W, Mo element content can increase the driving force for Laves phase precipitation, under the condition of auxiliary irradiation, the coarsening speed is extremely high, the solid solution strengthening effect of W, Mo element is reduced, and the coarsened Laves phase can also induce creep rupture to cause DBTT to rise. Therefore, how to regulate and control the trace elements in the ODS steel to achieve the optimal solution of the properties of the ODS steel remains a key research problem.

The mainstream preparation process of ODS steel comprises the steps of pre-alloy powder preparation, mechanical alloying, densification sintering, deformation processing, heat treatment and the like, and has the advantages of multiple process parameters, long preparation period and high research and development cost. The traditional mechanical alloying method has some defects, such as overlong ball milling time, low efficiency, easy introduction of impurities, certain oxidation of the prealloyed powder under the condition of long-time ball milling, and certain limitation on the content of the added elements. Therefore, Hot Extrusion (HE) or Hot Isostatic Pressing (HIP) methods have been developed to hot set the alloy powder after ball milling. ODS steel formed by HE has high density, but has anisotropy. While the ODS steel formed by HIP avoids anisotropy, the compactness is relatively poor. In addition, it has been found that the HE-formed ODS steel has higher tensile strength and hardness than HIP-formed ODS steel, and the oxide-strengthening phase is more uniformly dispersed. In addition to the two common forming methods, the ODS steel solidification forming method further includes spark plasma sintering (SPS sintering), Equal Channel Angular Extrusion (ECAE), microwave sintering, and the like. Wherein, the SPS sintering has the characteristics of heating time period and high density of the sintered body. The ECAE method is mainly characterized in that Cr-rich particles can be effectively refined, and Y2O3 nano particles are more uniformly distributed, so that the hardness of the material is improved. The microwave sintering can effectively reduce the sintering temperature and time, which not only can reduce the sintering cost, but also can not easily induce the large-scale growth of crystal grains because the sintering time is short and the fluidity of the crystal grain boundary is low, thereby obtaining finer crystal grains. But the existing ODS steel has complex regulation and control of components, more preparation process parameters, long research and development period and high cost; therefore, there is a strong need for a high-throughput preparation and component process optimization method of high-toughness ODS steel that can solve the above problems.

Disclosure of Invention

The invention aims to provide a high-flux preparation and component process optimization method for high-toughness ODS steel, which realizes the rapid optimization of ODS components and processes, prepares a kilogram-grade high-density ODS steel blank with high-density dispersion distribution ODS nano-phase, finally realizes the double halving of the development period and the cost, successfully prepares the high-toughness ODS steel plate which has the strength of more than 1.5GPa at room temperature, still keeps the high strength of more than 250MPa at 700 ℃ and still keeps better toughness.

The embodiment of the invention is realized by the following steps:

a high-flux preparation and component process optimization method of high-strength and high-toughness ODS steel comprises the following steps: s1: screening the existing high-flux components by a machine learning method to determine the optimal range of the components of the matrix alloy; s2: selected within the preferred rangeSelecting components of a sample to be prepared, and preparing prealloy powder of matrix alloy components by an atomization powder preparation method; s3: mixing the prepared prealloyed powder with Y₂O₃Uniformly mixing the powder by a high-energy ball mill to prepare ball-milled powder; s4: performing sheath and air extraction on the prepared ball-milled powder to prepare a powder blank; s5: repeating the steps S2-S4, selecting different components for preparation, and preparing ODS steel powder sheath samples under different components; s6: carrying out hot isostatic pressing synchronous sintering on ODS steel powder sheath samples with different components to prepare blanks with different components; s7: and cutting the blank sample into a wedge-shaped plate, carrying out high-temperature heat preservation treatment on the wedge-shaped plate, and carrying out single-pass flat rolling to prepare a rolled plate with the same thickness. The rapid optimization of ODS components and process is realized, kilogram-level high-density ODS steel blank with high-density dispersion distribution ODS nano-phase is prepared, the double halving of development period and cost is finally realized, and the high-strength and high-toughness ODS steel plate which has the strength of more than 1.5GPa at room temperature, still keeps the high strength of more than 250MPa at 700 ℃ and still keeps better toughness is successfully prepared.

Preferably, the preferred range in step S1 is obtained by a machine learning method based on the BP neural network algorithm.

Preferably, the prealloyed powder in step S2 is prepared by a vacuum induction melting method and an air atomization powder making method.

Preferably, the prealloyed powder is weighed and mixed with 0.3% high purity, Y2O3 powder in a glove box and transferred to a ball mill pot under argon atmosphere protection in step S3, and then the mixed powder is mechanically alloyed by a high energy planetary ball mill.

Preferably, the ball milling rotation speed in the step S3 is 600rpm, the ball milling time is 40h, and the ball-to-material ratio is 5: 1.

Preferably, in step S4, the mechanically alloyed powder is subjected to sheath evacuation at 400 ℃ for 10h with a vacuum degree of 10 or more^-1Pa。

Preferably, in step S6, hot isostatic pressing synchronous sintering is performed on powder sheath samples with different components, the reaction temperature is 1150 ℃, the pressure is 150MPa, and the holding time is 2 h.

Preferably, in step S7, the wedge-shaped plate is subjected to a high-temperature heat preservation treatment in an air furnace before rolling, the reaction temperature is 1150 ℃, and the heat preservation time is 30 min.

Preferably, the inclination of the wedge-shaped plate is 7-15 degrees, and the rolling strain rate is 1-10s^-1。

Preferably, 0-70% of the wedge-shaped plate is selected as a deformation interval according to the deformation of the wedge-shaped plate, plate crystal grains in the deformation interval are detected, and the optimal matrix alloy component and the deformation are obtained. The high-flux optimization of the deformation process is realized by preparing a gradient deformation sample through gradient rolling, and the matrix grain refinement and the ODS phase coarsening are inhibited by adopting the optimized rolling preparation process.

Due to the adoption of the technical scheme, the invention has the beneficial effects that: the invention discloses a high-flux preparation and component process optimization method of high-toughness ODS steel, which is characterized by comprising the following steps of: s1: screening the existing high-flux components by a machine learning method to determine the optimal range of the components of the matrix alloy; s2: selecting components of a sample to be prepared in an optimal range, and preparing prealloy powder of matrix alloy components by an atomization powder preparation method; s3: mixing the prepared prealloyed powder with Y₂O₃Uniformly mixing the powder by a high-energy ball mill to prepare ball-milled powder; s4: performing sheath and air extraction on the prepared ball-milled powder to prepare a powder blank; s5: repeating the steps S2-S4, selecting different components for preparation, and preparing ODS steel powder sheath samples under different components; s6: carrying out hot isostatic pressing synchronous sintering on ODS steel powder sheath samples with different components to prepare blanks with different components; s7: and cutting the blank sample into a wedge-shaped plate, carrying out high-temperature heat preservation treatment on the wedge-shaped plate, and carrying out single-pass flat rolling to prepare a rolled plate with the same thickness. Realizes the rapid optimization of ODS components and process, prepares and obtains kilogram-level high-density ODS steel blank with high-density dispersion distribution ODS nano-phase, finally realizes the double reduction of research and development period and cost by half, successfully prepares and obtains the ODS steel blank with the strength of more than 1.5GPa at room temperature, still maintains the high strength of more than 250MPa at 700 ℃, and still maintains better toughnessThe high-strength and high-toughness ODS steel plate.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic view showing the composition of a high-toughness ODS steel in the present invention;

FIG. 2 is a schematic diagram of powder preparation and multi-component simultaneous sintering according to the present invention;

FIG. 3 is a schematic view of wedge rolling in the present invention;

FIG. 4 is a microscopic view of ODS steel prepared in the present invention;

FIG. 5 is a graph showing the tensile properties of ODS steel in accordance with the present invention;

FIG. 6 is a diagram of the method steps of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Example 1: referring to fig. 1 to 6, the preferred method for preparing high-flux and high-toughness ODS steel with high composition process of the present embodiment includes the following steps: s1: screening the existing high-flux components by a machine learning method to determine the optimal range of the components of the matrix alloy; s2: selecting components of a sample to be prepared in an optimal range, and preparing prealloy powder of matrix alloy components by an atomization powder preparation method; s3: mixing the prepared prealloyed powder with Y₂O₃Uniformly mixing the powder by a high-energy ball mill to prepare ball-milled powder; s4: for preparation ofPerforming sheath and air extraction on the obtained ball-milled powder to prepare a powder blank; s5: repeating the steps S2-S4, selecting different components for preparation, and preparing ODS steel powder sheath samples under different components; s6: carrying out hot isostatic pressing synchronous sintering on ODS steel powder sheath samples with different components to prepare blanks with different components; s7: and cutting the blank sample into a wedge-shaped plate, carrying out high-temperature heat preservation treatment on the wedge-shaped plate, and carrying out single-pass flat rolling to prepare a rolled plate with the same thickness. The rapid optimization of ODS components and process is realized, kilogram-level high-density ODS steel blank with high-density dispersion distribution ODS nano-phase is prepared, the double halving of development period and cost is finally realized, and the high-strength and high-toughness ODS steel plate which has the strength of more than 1.5GPa at room temperature, still keeps the high strength of more than 250MPa at 700 ℃ and still keeps better toughness is successfully prepared.

Example 2: the preferred range in step S1 of the present embodiment is obtained by a machine learning method based on the BP neural network algorithm. The prealloyed powder in step S2 of this example was produced by vacuum induction melting and gas atomization powder production. In step S3, the prealloyed powder was weighed and mixed with 0.3% high purity, Y2O3 powder in a glove box and transferred to a ball mill pot under argon atmosphere protection, and then the mixed powder was mechanically alloyed by a high energy planetary ball mill. In step S3 of this example, the ball milling rotation speed was 600rpm, the ball milling time was 40 hours, and the ball-to-material ratio was 5: 1. In step S4, the sheath evacuation process is performed on the mechanically alloyed powder at 400 ℃ for 10 hours with a vacuum degree of 10 or more^-1Pa. In step S6, the hot isostatic pressing synchronous sintering is performed on the powder capsule samples with different compositions, the reaction temperature is 1150 ℃, the pressure is 150MPa, and the holding time is 2 h. In step S7, the wedge-shaped plate is subjected to a high temperature heat preservation treatment in an air furnace before rolling, the reaction temperature is 1150 ℃, and the heat preservation time is 30 min. The inclination of the wedge-shaped plate of the embodiment is 7-15 degrees, and the rolling strain rate is 1-10s^-1. In this embodiment, 0-70% of the wedge-shaped plate is selected as a deformation zone according to the deformation amount of the wedge-shaped plate, and the plate crystal grains in the deformation zone are detected and obtainedThe optimum base alloy composition and amount of deformation. The high-flux optimization of the deformation process is realized by preparing a gradient deformation sample through gradient rolling, and the matrix grain refinement and the ODS phase coarsening are inhibited by adopting the optimized rolling preparation process.

Example 3: the method specifically comprises the following steps:

(1) the high-flux component process is preferably as follows: and (4) predicting the mechanical properties of the ODS steel with different components by using a BP (Back propagation) neural network, thereby determining the preferable range of each component. The data used in the neural network is obtained by collecting 200-300 groups of experimental data, and each group of data comprises components, processing technology, tensile property data and the like of ODS steel. And after screening the data, determining elements in the ODS steel, the forming process temperature and type and the tensile test temperature as the input of a neural network. And the room temperature strength, room temperature plasticity, high temperature strength and high temperature plasticity of the ODS steel are used as the output of the neural network. The number of training sets was 77 and the number of test sets was 12. As shown in FIG. 1, after high-throughput calculation and screening, the ODS steel alloy components are determined as follows: fe-13.5Cr-2W-0.3Y-0.3Ti-0.3Y2O3, Fe-13.5Cr-2W-4.5Al-0.3Y2O3 and Fe-13.5Cr-2W-4.5Al-0.3Ti-0.3Y2O 3.

(2) Preparing prealloying powder: obtaining prealloy powder with the mass fraction of Fe-13.5Cr-2W-0.3Y-0.3Ti through vacuum induction melting and gas atomization powder preparation, wherein the granularity of the powder is about 70 microns.

(3) Mechanical alloying: the prealloyed powder of Fe-13.5Cr-2W-0.3Y-0.3Ti and 0.3% high purity Y2O3 powder were weighed and mixed in a glove box and transferred to a ball mill under the protection of argon atmosphere. And then, carrying out mechanical alloying on the mixed powder by a high-energy planetary ball mill, wherein the ball milling rotation speed is 600rpm, the ball milling time is 40h, and the ball-material ratio is 5: 1. To prevent oxidation, the sampling process was performed in a glove box with high purity argon.

(4) Sealing and degassing: performing sheath air exhaust process on the powder after mechanical alloying: the temperature is 400 ℃, the heat preservation time is 10 hours, and the vacuum degree is not less than 10^-1Pa。

And (3) repeating the steps (1) and (3) to finally obtain the powder sheath samples with the components of Fe-13.5Cr-2W-0.3Y-0.3Ti-0.3Y2O3, Fe-13.5Cr-2W-4.5Al-0.3Y2O3 and Fe-13.5Cr-2W-4.5Al-0.3Ti-0.3Y2O 3.

(5) Multi-component synchronous sintering: as shown in fig. 2, 3 powder capsule samples of different composition and process were hot isostatic pressed for simultaneous sintering at 1150 ℃, pressure: 150MPa and the heat preservation time is 2 h.

(6) Wedge rolling: as shown in FIG. 3, a blank sample was cut into a wedge-shaped plate having a right angle of 7 degrees, heat-preserved in an air furnace at 1150 ℃ for 30min before rolling, and then subjected to single pass flat rolling using a common hot rolling mill having a roll diameter of 200cm to obtain a rolled plate having a uniform thickness at a rolling strain rate of 10s^-1. Wherein, the addition of Y2O3 has obvious fine crystal effect. After hot rolling, the carbide inclusions are redissolved, the grain refining effect is obvious, and the grain morphology is not obviously influenced. The matrix after hot rolling is of a full ferrite structure.

The high-flux preparation method of the high-strength and high-toughness ODS steel is preferably 3 ODS steels with different components, namely Fe-13.5Cr-2W-0.3Y-0.3Ti-0.3Y2O3, Fe-13.5Cr-2W-4.5Al-0.3Y2O3 and Fe-13.5Cr-2W-4.5Al-0.3Ti-0.3Y2O 3. Through multi-component synchronous sintering and wedge rolling, the quick optimization of ODS components and processes is realized, and kilogram-level high-density ODS steel blanks with high-density dispersion distribution ODS nano-phases are prepared and obtained, as shown in FIG. 4. Meanwhile, the high-flux optimization of the deformation process is successfully realized by utilizing the gradient rolling process. And the preferable rolling preparation process is adopted to refine the matrix grains and inhibit the coarsening of the ODS phase, so that the obdurability of the ODS steel is effectively realized. As shown in FIG. 5, the room temperature mechanical strength of the plate can reach more than 1.5GPa, and the high temperature (700 ℃) strength is kept at more than 250MPa, and meanwhile, the plate still keeps good toughness.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.