阅读说明：本技术 一种高强塑积中熵合金带材的制备方法 (Preparation method of high-strength-ductility medium-entropy alloy strip ) 是由 衣海龙 徐伟 杨寿奎 杨康 于 2020-07-31 设计创作，主要内容包括：本发明的一种高强塑积中熵合金带材的制备方法,属于金属板带材轧制与热处理技术领域,制备过程为：按成分比例,制备(FeCoNi)<Sub>76-</Sub><Sub>84</Sub>Ti<Sub>8-12</Sub>Al<Sub>8-12</Sub>中熵合金作坯料,加热至1150-1250℃,保温45-60min,降温至950-1050℃,恒温轧制后淬火至室温,475-525℃保温20-40min,恒温轧制,应变速率为10-20s<Sup>-1</Sup>,应变量为50％-60％,轧后淬火至室温,经室温冷轧,总变形量为70％-80％,得到1-3mm厚冷轧板材,780-820℃下退火保温45-60min后,淬火至室温,制得带材产品。该工艺结合特定的热轧、冷轧及热处理工艺制备方法,获得的中熵合金带材具有更高的强塑积,该制备方法流程简单,可操作性强,可为批量化生产高强塑积板带材提供高效的制备工艺。(The invention discloses a preparation method of a high-strength-plasticity medium-entropy alloy strip, belonging to the technical field of rolling and heat treatment of metal plates and strips, and the preparation process comprises the following steps: preparing (FeCoNi) according to the component proportion 76‑ 84 Ti 8‑12 Al 8‑12 Heating the medium entropy alloy as a blank to 1150-1250 ℃, preserving heat for 45-60min, cooling to 950-1050 ℃, quenching to room temperature after constant temperature rolling, preserving heat for 20-40min at 475-525 ℃, and rolling at constant temperature with the strain rate of 10-20s ‑1 The strain is 50-60%, quenching is carried out to room temperature after rolling, the total deformation is 70-80% after cold rolling at room temperature, a cold-rolled plate with the thickness of 1-3mm is obtained, annealing and heat preservation are carried out at 780-dash 820 ℃ for 45-60min, and then quenching is carried out to room temperature, and a strip product is prepared. The process is combined with a specific hot rolling, cold rolling and heat treatment process preparation method, the obtained medium-entropy alloy strip has a higher product of strength and elongation, the preparation method is simple in flow and strong in operability, and can be used for batch productionThe high-strength plastic laminated plate strip provides an efficient preparation process.)

1. The preparation method of the high-strength-ductility medium-entropy alloy strip is characterized in that the strip is (FeCoNi)_{76- 84}Ti_8-12Al_8-12The high-strength-plastic-product medium-entropy alloy strip comprises recrystallized grains and unrecrystallized grains, and the mass ratio of the recrystallized grains to the unrecrystallized grains is as follows: 60% -70% of recrystallized grains and 30% -40% of unrecrystallized grains;

the method comprises the following steps:

(1) preparing (FeCoNi) according to the component proportion_76-84Ti_8-12Al_8-12The medium entropy alloy is used as a blank, and the atomic percentages of Fe, Co and Ni are 1: 1: 1; heating to 1150-1250 ℃, preserving heat for 45-60min, cooling to 950-1050 ℃, rolling at high temperature and constant temperature with strain rate of 0.01-0.02s^-1Quenching to room temperature after rolling to obtain a high-temperature rolled plate;

(2) keeping the plate subjected to high-temperature rolling in a 475-525 ℃ heating furnace for 20-40min, and then carrying out medium-temperature constant-temperature rolling at the strain rate of 10-20s^-1The strain is 50% -60%, and the rolled plate is quenched to room temperature to obtain a medium-temperature rolled plate;

(3) cold rolling the plate after medium-temperature rolling at room temperature to obtain a cold-rolled plate with the thickness of 1-3mm, wherein the total deformation is 70% -80%;

(4) and heating the cold-rolled sheet in an annealing furnace, preserving heat, and then quenching to room temperature to prepare the high-strength-plasticity medium-entropy alloy strip, wherein the temperature of the annealing furnace is 780-820 ℃, and the annealing heat preservation time is 45-60 min.

2. A method for preparing a high-product-of-strength-product intermediate-entropy alloy strip according to claim 1, wherein in the step (1), the austenite grain size in the blank after heating and heat preservation is 100-150 μm; after high-temperature and constant-temperature rolling, partial recrystallization occurs, wherein the recrystallization occurrence ratio is 60% -70%, the size of recrystallized grains is 3-5 mu m, and the rest is a flattened unrecrystallized austenite structure.

3. The method for preparing the high-product-of-strength-product intermediate-entropy alloy strip according to claim 1, wherein in the step (4), the cold-rolled sheet is subjected to heating and heat preservation and then subjected to partial recrystallization annealing, wherein the recrystallization proportion is 70% -80%, the recrystallized grain size is 1-3 μm, and the balance is a flattened non-recrystallized austenite structure.

4. The method for preparing the high-strength-product medium-entropy alloy strip according to claim 1, wherein in the step (4), the prepared high-strength-product medium-entropy alloy strip is accompanied by Ni₃(Al, Ti) precipitates having a precipitate size of 3 to 5 nm.

5. The method for preparing the high-strength-product intermediate-entropy alloy strip as claimed in claim 1, wherein in the step (4), the prepared high-strength-product intermediate-entropy alloy strip has a tensile strength of 2000-2100MPa, a plasticity of 40% -50%, and a strength-product of 84-100 GPa%.

The technical field is as follows:

the invention belongs to the technical field of rolling and heat treatment of metal plate strips, and particularly relates to a preparation method of a high-strength-plastic-product medium-entropy alloy strip.

Background art:

in recent years, the design concept of the high-entropy alloy is provided, the traditional alloy design theory mainly based on a single element is broken through, and the high-entropy alloy material has remarkable comprehensive effects of a high-entropy effect, a lattice distortion effect, a delayed diffusion effect and the like, so that a new thought is provided for the research and development of materials with high strength, high plasticity, corrosion resistance, wear resistance and the like. Compared with the multi-component high-entropy alloy, the medium-entropy alloy is mainly a ternary or quaternary alloy, and the improvement of the comprehensive properties such as strength, plasticity or corrosion resistance is achieved by adding a small amount of other alloy elements, and although the main alloy elements are reduced, the potential excellent comprehensive properties still attract the wide attention of the industrial fields such as aerospace, automobile industry and nuclear energy industry. Compared with final use forms such as a solidification state, a sintering state and the like, the plate and strip have wider application prospects, the production efficiency of the plate and strip rolling and heat treatment process flow is high, and a more efficient production process flow is provided for batch preparation of the high-added-value medium-entropy alloy.

The precipitation strengthening type medium entropy alloy mainly based on FeCoNi has good plasticity in a complete annealing state, but the strength is low, and due to the fact that the precipitation strengthening type medium entropy alloy is of an FCC structure, although the strength can be improved by adopting fine grain strengthening and precipitation strengthening, the plasticity can be obviously reduced, and a large amount of research work shows that the conventional fine grain strengthening process is limited in improvement amplitude. Therefore, the traditional preparation method has limited technological means for greatly improving the product of intermediate entropy alloy strength and elongation, and is difficult to exert the potential of the material to the maximum extent.

Chinese patent documents CN108677077A and CN110541103A respectively report a high-specific-strength high-plasticity refractory high-entropy alloy and a preparation method thereof, a high-strength high-plasticity quaternary refractory high-entropy alloy and a preparation method thereof, and a smelting process of a complex heteroalloy element is described in detail. Chinese patent document CN110863124A reports a high-strength high-plasticity medium entropy alloy and a preparation method thereof, the composition of which is Cu: 45% -58%, Mn: 22% -30%, Ni: 10% -15%, Al: 3% -8%, Y: 0.5 to 2 percent, and the preparation steps are pretreatment → smelting alloy → die casting. None of the above patents relate to the subsequent rolling and heat treatment process.

Chinese patent document CN110499451A reports a high-strength high-plasticity wear-resistant high-entropy alloy and a preparation method thereof, and the high-strength high-plasticity wear-resistant high-entropy alloy comprises the following components: 54% -56%, Co: 9% -11%, Ni: 9% -11%, Cr: 9% -11%, Mo: 4% -6%, V: 4% -6%, C: 4% -6%, the preparation steps are casting → homogenizing → hot rolling → annealing, and the parameters of the hot rolling process and the annealing process are limited, the plasticity and the toughness are improved based on dislocation slippage and mechanical twinning of austenite, and the strength and the wear resistance are improved by regulating and controlling carbide, but the alloy is a multi-component high-entropy alloy, the corresponding tensile strength is low, the wear resistance of the high-entropy alloy is improved, and the actual wear resistance of the alloy reaches 80% of that of M2 high-speed steel.

In conclusion, for the medium entropy alloy with the FCC structure, particularly for the plate strip, the preparation method for regulating and controlling the product of strength and elongation is single, and the comprehensive performance of the material is difficult to be greatly improved.

The invention content is as follows:

the invention aims to overcome the defects in the prior art, provides a preparation method of a high-strength-plasticity medium-entropy alloy strip in order to furthest improve the strength-plasticity product of the medium-entropy alloy strip, is suitable for separating out a reinforced medium-entropy alloy from an FCC system, can continuously and efficiently prepare the high-strength-plasticity medium-entropy alloy strip, can be widely applied to the plate application fields of the automobile industry, the nuclear energy industry and the like, and provides reference for the preparation of other high-strength-plasticity high-entropy alloy strips.

In order to achieve the purpose, the invention adopts the following technical scheme:

a high-strength-ductility medium-entropy alloy strip, specifically (FeCoNi)_76-84Ti_8-12Al_8-12The high-strength-plastic-product medium-entropy alloy strip comprises recrystallized grains and unrecrystallized grains, and the mass ratio of the recrystallized grains to the unrecrystallized grains is as follows: 60% -70% of recrystallized grains and 30% -40% of unrecrystallized grains.

The tensile strength of the entropy alloy strip with high strength-elongation product is 2100MPa, the plasticity is 40-50%, and the strength-elongation product reaches 84-100 GPa%.

The preparation method of the high-strength-plastic-product medium-entropy alloy strip comprises the following steps:

(1) preparing (FeCoNi) according to the component proportion_76-84Ti_8-12Al_8-12The medium entropy alloy is used as a blank, and the atomic percentages of Fe, Co and Ni are 1: 1: 1; heating to 1150-1250 ℃, preserving heat for 45-60min, cooling to 950-1050 ℃, rolling at high temperature and constant temperature with strain rate of 0.01-0.02s^-1Quenching to room temperature after rolling to obtain a high-temperature rolled plate;

in the step (1), the austenite grain size in the blank after heating and heat preservation is 100-150 μm; after high-temperature and constant-temperature rolling, partial recrystallization occurs, wherein the recrystallization occurrence ratio is 60% -70%, the size of recrystallized grains is 3-5 mu m, and the rest is a flattened unrecrystallized austenite structure.

(2) Keeping the plate subjected to high-temperature rolling in a 475-525 ℃ heating furnace for 20-40min, and then carrying out medium-temperature constant-temperature rolling at the strain rate of 10-20s^-1The strain is 50% -60%, and the rolled plate is quenched to room temperature to obtain a medium-temperature rolled plate;

(3) cold rolling the plate after medium-temperature rolling at room temperature to obtain a cold-rolled plate with the thickness of 1-3mm, wherein the total deformation is 70% -80%;

(4) and heating the cold-rolled sheet in an annealing furnace, preserving heat, and then quenching to room temperature to prepare the high-strength-plasticity medium-entropy alloy strip, wherein the temperature of the annealing furnace is 780-820 ℃, and the annealing heat preservation time is 45-60 min.

In the step (4), after the cold-rolled sheet is heated and insulated, partial recrystallization annealing is carried out, wherein the recrystallization occurrence ratio is 70-80%, the size of recrystallized grains is 1-3 mu m, and the rest is a flattened unrecrystallized austenite structure.

In the step (4), Ni is accompanied in the prepared high-strength-plasticity medium-entropy alloy strip₃(Al, Ti) precipitates having a precipitate size of 3 to 5 nm.

The principle of the invention is as follows: the initial structure with the characteristics of a partially recrystallized structure is prepared by specific high-temperature constant-temperature rolling, strain accumulation is carried out by subsequent combination with medium-temperature rolling, at the moment, the alloy is not recrystallized, the obvious strain accumulation effect is achieved, and the strain energy storage of the alloy is obviously improved by combination with the subsequent cold rolling process. The specific annealing process is controlled, partial recrystallization annealing is carried out near the critical recrystallization temperature, the tissue and precipitation regulation and control process is considered, and the high-strength and high-plasticity performance of the medium-entropy alloy strip is obtained by utilizing the synergistic deformation mechanism of fine-grain strengthening, precipitation strengthening and tissues with different grain sizes.

The invention has the beneficial effects that:

the preparation process of the invention combines the specific preparation methods of hot rolling, cold rolling and heat treatment to obtain (FeCoNi)_76-84Ti_8-12Al_8-12The precipitation-strengthened type medium-entropy alloy has a higher product of strength and elongation, the preparation method is simple in process and strong in operability, and an efficient preparation process can be provided for batch production of high-product-of-strength-elongation plate strips.

The specific implementation mode is as follows:

the present invention will be described in further detail with reference to examples.

A high-strength-ductility medium-entropy alloy strip, specifically (FeCoNi)_76-84Ti_8-12Al_8-12The high-strength-plastic-product medium-entropy alloy strip comprises recrystallized grains and unrecrystallized grains, and the mass ratio of the recrystallized grains to the unrecrystallized grains is as follows: 60% -70% of recrystallized grains and 30% -40% of unrecrystallized grains.

The preparation method of the high-strength-ductility medium-entropy alloy strip comprises the following steps:

(1) selecting (FeCoNi)_76-84Ti_8-12Al_8-12The medium entropy alloy is used as a blank, and the atomic percentages of Fe, Co and Ni are 1: 1: 1; heating to 1150-1250 ℃, keeping the temperature for 45-60min, then carrying out high-temperature constant-temperature rolling after the austenite grain size in the blank is 100-150 mu m and cooling to 950-1050 ℃, wherein the strain rate is 0.01-0.02s^-1After high-temperature rolling, partially recrystallizing the blank, wherein the recrystallization proportion is 60-70%, the recrystallized grain size is 3-5 mu m, and the rest is a flattened non-recrystallized austenite structure, and quenching to room temperature after rolling to obtain a high-temperature rolled plate;

(2) keeping the plate subjected to high-temperature rolling in a 475-525 ℃ heating furnace for 20-40min, and then carrying out medium-temperature constant-temperature rolling at the strain rate of 10-20s^-1The strain amount is 50 percent60 percent, quenching to room temperature after rolling to obtain a medium-temperature rolled plate;

(3) cold rolling the plate after medium-temperature rolling at room temperature to obtain a cold-rolled plate with the thickness of 1-3mm, wherein the total deformation is 70% -80%;

(4) heating the cold-rolled sheet in an annealing furnace, preserving heat, performing partial recrystallization annealing, wherein the recrystallization occurrence ratio is 70-80%, the size of recrystallized grains is 1-3 mu m, the rest is a flattened non-recrystallized austenite structure, then quenching to room temperature to prepare the high-strength-plasticity product intermediate entropy alloy strip, wherein the temperature of the annealing furnace is 780-doped-grain 820 ℃, the annealing heat preservation time is 45-60min, and the prepared high-strength-plasticity product intermediate entropy alloy strip is accompanied by Ni₃The size of the (Al, Ti) precipitate is 3-5nm, the tensile strength of the strip is 2000-2100MPa, the plasticity is 40% -50%, and the product of strength and elongation reaches 84-100 GPa%.