CN104152781B - A kind of preparation method of AlCoCuFeNiSi high-entropy alloy - Google Patents

Abstract

A preparation method of AlCoCuFeNiSi high-entropy alloy. The invention relates to a preparation method of a high-entropy alloy. The purpose of the invention is to solve the problem of low heat resistance of existing structural steels. Methods: 1. Ultrasonic treatment: Al material, Co material, Cu material, Fe material, Ni material and Si material were ultrasonically cleaned successively with acetone solution and absolute ethanol; 2. Weighing: weigh alloy materials in equimolar amounts; . Melting the high-entropy alloy: obtaining an ellipsoidal AlCoCuFeNiSi high-entropy alloy ingot. The advantages of the invention: the AlCoCuFeNiSi high-entropy alloy prepared by the invention has a simple body-centered cubic structure and a face-centered cubic structure, the yield strength is as high as 1781.6 MPa, and the fracture strength is as high as 1895.2 MPa. The high-entropy alloy of the invention can be used as a structural material for bearing structures in heat-resistant fields such as power station boilers.

Description

A kind of preparation method of AlCoCuFeNiSi high entropy alloy

technical field

The invention relates to a preparation method of a high-entropy alloy.

Background technique

For a long time, the traditional alloy design method is to use one or two elements as the main components, and then add other elements to improve the structure and properties of the material, such as stainless steel, Ti-Al and other binary intermetallic compounds, aluminum alloys, titanium alloys, magnesium alloys, and bulk amorphous alloys. The traditional crystallographic theory believes that too many components in the alloy will lead to the formation of various intermetallic compounds and other complex structures, making the alloy lose its mechanical properties and making it difficult to obtain practical applications. With the development of modern industry, higher and higher performance requirements are put forward for materials: excellent mechanical properties, high temperature resistance, corrosion resistance, soft magnetic properties, etc., although improved by new material processing technologies such as rapid solidification and laser processing The performance of the material, but still can not meet the requirements of industrial applications.

On the other hand, after hundreds of years of development, the development of traditional alloy systems has become saturated. It has become an inevitable requirement for the development of metal materials to break through the design ideas of traditional alloys based on one or two metal elements. High-entropy alloys are developed under this trend.

In 2004, Professor Ye Junwei, a Taiwanese scholar, completely broke the traditional single principal element design mode of alloys and created a new research field of metal materials. High-entropy alloys are no longer dominated by a single element, but in the form of multiple main elements. Professor Ye Junwei believes that after the solidification of multi-principal alloys, not only will not form a large number of intermetallic compounds, but will form simple body-centered cubic or face-centered cubic phases, and the number of phases obtained is far lower than the number of phases predicted by the equilibrium phase ratio. He believes this is due to the high mixing entropy of multi-principal alloys, which suppresses the emergence of intermetallic compounds. Furthermore, the multi-principal alloy is named multi-principal high-entropy alloy, and the definition of multi-principal high-entropy alloy is given: the number of main elements is n≥5, and the atomic percentage of each main element is 5% to 35%. alloy. Therefore, in the multi-principal element high-entropy alloy, none of the components will exceed 50% in quantity, and then become the only main element. The proposal of multi-principal alloy design concept has opened up a vast new alloy system. Multi-principal alloys have excellent properties, including high hardness, large work hardening, high temperature softening resistance, corrosion resistance and high electrical resistivity, which make the application level of high entropy alloys colorful, such as high hardness, wear resistance, temperature resistance and corrosion resistance Tools, moulds, knives; hard surfaces of golf ring heads, hydraulic and air rods, steel pipes and rollers; high-frequency transformers, motor cores, carbon shields, magnetic heads, magnetic disks, magneto-optical disks, high-frequency soft magnetic film materials ; Corrosion-resistant high-strength materials for chemical plants and ships; refractory materials for turbine blades, welding materials, heat exchange heat exchangers and high-temperature furnaces, refractory skeletons for super-tall buildings, anti-diffusion films for sprayed metal materials, and micro-electromechanical materials Wait. Due to the diversified application potential and broad prospects for industrial diversification, the research and development of multi-principal alloys is undoubtedly of great significance to the improvement of traditional metallurgy and iron and steel industries. Therefore, it is of great significance to develop AlCoCuFeNiSi high-entropy alloys with good mechanical properties.

Heat-resistant structural materials are required in heat-resistant applications such as power plant boilers. The thermal stability of high-entropy alloys can exert their excellent performance in such applications. How to develop high-entropy alloys with high strength to meet the service requirements of high-temperature environments , has become the prerequisite for high-entropy alloys to move towards large-scale industrial applications, and is also a realistic demand for the development of new materials in high-temperature service environments.

Contents of the invention

The purpose of the present invention is to solve the problem of low heat resistance of existing structural steels, and provide a preparation method of AlCoCuFeNiSi high-entropy alloy.

A kind of AlCoCuFeNiSi high-entropy alloy of the present invention is made up of Al, Co, Cu, Fe, Ni and Si element;

The molar ratio of any two elements in the AlCoCuFeNiSi high-entropy alloy is 1:1.

A kind of preparation method of AlCoCuFeNiSi high-entropy alloy of the present invention is specifically finished according to the following steps:

1. Ultrasonic treatment: put Al material, Co material, Cu material, Fe material, Ni material and Si material in a container, then add acetone solution, and ultrasonically clean for 20min to 30min to remove oil and impurities attached to the surface, and obtain impurity removal Al material, Co material, Cu material, Fe material, Ni material and Si material, and then the Al material, Co material, Cu material, Fe material, Ni material and Si material after impurity removal are placed in the container, and no Ultrasonic cleaning with water and ethanol for 20 minutes to 30 minutes, and then drying in a drying box to obtain Al materials, Co materials, Cu materials, Fe materials, Ni materials and Si materials after ultrasonic treatment;

2. Weighing materials: Weigh the ultrasonically treated Al material, Co material, Cu material, Fe material, Ni material and Si material obtained in step 1 of equimolar amounts;

3. Smelting high-entropy alloys: ① Put titanium sponge into a smelting pool of a water-cooled copper mold, and then place the ultrasonically treated Al material, Co material, Cu material, Fe material, Ni material and Si material in step 2. In another smelting pool of the water-cooled copper mold, according to the melting point of each material, the melting point of the material is placed from the bottom to the top. After the materials are placed, cover the furnace cover and tighten the knob of the sample chamber; ② Vacuum the melting furnace, Fill in argon gas at a vacuum of 1×10 ^-3 Pa until the pressure is 0.5atm~1atm; ③Repeat step ②3 to 5 times; ④Repeat the smelting of sponge titanium for 3 times~ 5 times, smelting for 60s-120s each time; ⑤ Under the condition of smelting current of 250A-300A, smelting the Al material, Co material, Cu material, Fe material, Ni material and Si material after ultrasonic treatment in step 2 of step ① 60s to 120s for the material to obtain an ingot; ⑥Turn over the ingot after step ⑤, and then melt for 60s to 120s under the condition of a smelting current of 250A to 300A; ⑦Repeat step ⑥6 to 7 times, and cool with the furnace to obtain an Spherical AlCoCuFeNiSi high-entropy alloy; the mass of the titanium sponge described in step ① is 40g-100g.

In the present invention, the purpose of step 2. and step 3. is to wash the gas, and repeatedly charge and discharge argon to minimize the air content of the smelting furnace.

The purpose of step ④ in the present invention is to make residual oxygen be eliminated as much as possible by smelting sponge titanium.

Advantages of the present invention: the AlCoCuFeNiSi high-entropy alloy prepared by the present invention has excellent mechanical properties. The high-entropy alloy has a simple body-centered cubic structure and a face-centered cubic structure, and has very high yield strength and fracture strength, and the yield strength is as high as 1781.6MPa , the fracture strength is as high as 1895.2MPa, which makes it meet the requirements of the mechanical properties of materials in modern industry, making high-entropy alloys widely used in the industrial field.

Description of drawings

Fig. 1 is the XRD spectrum of the AlCoCuFeNiSi high-entropy alloy prepared in Test 1;

Fig. 2 is the microstructure (X1000) photo of the AlCoCuFeNiSi high-entropy alloy prepared by test one;

Fig. 3 is the microstructure (X4000) photo of the AlCoCuFeNiSi high-entropy alloy prepared by test one;

Figure 4 is the EDX analysis histogram of the AlCoCuFeNiSi high-entropy alloy prepared in Experiment 1; 1 is the Cu/Al-rich phase, Cu ₃ Al-like; 2 is the Cu-poor phase; 3 is the dendrite phase whose composition is close to the nominal composition.

Fig. 5 is the Al element surface distribution diagram of the AlCoCuFeNiSi high-entropy alloy prepared in test one;

Fig. 6 is the Co element surface distribution figure of the AlCoCuFeNiSi high-entropy alloy prepared in test one;

Fig. 7 is the surface distribution diagram of Cu element of AlCoCuFeNiSi high-entropy alloy prepared in test one;

Fig. 8 is the surface distribution diagram of Fe element of AlCoCuFeNiSi high-entropy alloy prepared in test one;

Fig. 9 is the surface distribution diagram of the Ni element of the AlCoCuFeNiSi high-entropy alloy prepared in Test 1;

Fig. 10 is the Si element surface distribution diagram of the AlCoCuFeNiSi high-entropy alloy prepared in test one;

Fig. 11 is the true strain-true stress curve diagram of the AlCoCuFeNiSi high-entropy alloy prepared in test one;

Fig. 12 is a compression fracture morphology diagram of the AlCoCuFeNiSi high-entropy alloy prepared in Test 1;

Fig. 13 is an enlarged view at a in Fig. 12 .

detailed description

Specific embodiment one: a kind of AlCoCuFeNiSi high-entropy alloy of this embodiment is composed of Al, Co, Cu, Fe, Ni and Si elements;

The molar ratio of any two elements in the AlCoCuFeNiSi high-entropy alloy is 1:1.

Specific embodiment two: the preparation method of a kind of AlCoCuFeNiSi high-entropy alloy of this embodiment is specifically completed according to the following steps:

1. Ultrasonic treatment: put Al material, Co material, Cu material, Fe material, Ni material and Si material in a container, then add acetone solution, and ultrasonically clean for 20min to 30min to remove oil and impurities attached to the surface, and obtain impurity removal Al material, Co material, Cu material, Fe material, Ni material and Si material, and then the Al material, Co material, Cu material, Fe material, Ni material and Si material after impurity removal are placed in the container, and no Ultrasonic cleaning with water and ethanol for 20 minutes to 30 minutes, and then drying in a drying box to obtain Al materials, Co materials, Cu materials, Fe materials, Ni materials and Si materials after ultrasonic treatment;

2. Weighing materials: Weigh the ultrasonically treated Al material, Co material, Cu material, Fe material, Ni material and Si material obtained in step 1 of equimolar amounts;

3. Smelting high-entropy alloys: ① Put titanium sponge into a smelting pool of a water-cooled copper mold, and then place the ultrasonically treated Al material, Co material, Cu material, Fe material, Ni material and Si material in step 2. In another smelting pool of the water-cooled copper mold, according to the melting point of each material, the melting point of the material is placed from the bottom to the top. After the materials are placed, cover the furnace cover and tighten the knob of the sample chamber; ② Vacuum the melting furnace, Fill in argon gas at a vacuum of 1×10 ^-3 Pa until the pressure is 0.5atm~1atm; ③Repeat step ②3 to 5 times; ④Repeat the smelting of sponge titanium for 3 times~ 5 times, smelting for 60s-120s each time; ⑤ Under the condition of smelting current of 250A-300A, smelting the Al material, Co material, Cu material, Fe material, Ni material and Si material after ultrasonic treatment in step 2 of step ① 60s to 120s for the material to obtain an ingot; ⑥Turn over the ingot after step ⑤, and then melt for 60s to 120s under the condition of a smelting current of 250A to 300A; ⑦Repeat step ⑥6 to 7 times, and cool with the furnace to obtain an Spherical AlCoCuFeNiSi high-entropy alloy; the mass of the titanium sponge described in step ① is 40g-100g.

In the present invention, the purpose of step 2. and step 3. is to wash the gas, and repeatedly charge and discharge argon to minimize the air content of the smelting furnace.

The purpose of step ④ in the present invention is to make residual oxygen be eliminated as much as possible by smelting sponge titanium.

Embodiment 3: This embodiment differs from Embodiment 2 in that the purity of the Al material, Co material, Cu material, Fe material, Ni material and Si material described in step 1 are all ≥99.9%. Other steps and parameters are the same as in the second embodiment.

Embodiment 4: The difference between this embodiment and Embodiment 2 or 3 is that the forms of the Al material, Co material, Cu material, Fe material, Ni material and Si material described in step 1 are all except powder. status. Other steps and parameters are the same as those in Embodiment 2 or 3.

This embodiment is to ensure that there is no loss of material under the blow force of the arc.

Embodiment 5: This embodiment differs from Embodiment 2 to Embodiment 4 in that the Al material, Co material, Cu material, Fe material, Ni material and Si material described in step 1 are all in the form of blocks , flake or filament. Other steps and parameters are the same as those in the second to fourth specific embodiments.

Specific embodiment 6: The difference between this embodiment and one of specific embodiments 2 to 5 is that: in the step 1, it is placed in a drying box for drying, and the drying process is at a temperature of 40 to 60 ° C. Dry under the same conditions for 20min to 40min. Other steps and parameters are the same as one of the second to fifth specific embodiments.

Embodiment 7: This embodiment differs from Embodiment 2 to Embodiment 6 in that it is placed in a drying box for drying as described in step 1, and the drying process is at a temperature of 50°C. Dry for 30min. Other steps and parameters are the same as those in the second to sixth specific embodiments.

Adopt following test to verify beneficial effect of the present invention:

Test one, the preparation method of a kind of AlCoCuFeNiSi high-entropy alloy of this test is carried out according to the following steps:

1. Ultrasonic treatment: put Al material, Co material, Cu material, Fe material, Ni material and Si material in a container, then add acetone solution, ultrasonically clean for 25 minutes, remove oil and impurities attached to the surface, and obtain the impurity-removed Al material, Co material, Cu material, Fe material, Ni material and Si material, then put the Al material, Co material, Cu material, Fe material, Ni material and Si material in the container after removing impurities, add absolute ethanol Ultrasonic cleaning for 25 minutes, and then placed in a drying box for drying, to obtain Al material, Co material, Cu material, Fe material, Ni material and Si material after ultrasonic treatment;

2. Weighing materials: Weigh 3.6950g of Al material, 8.0707g of Co material, 8.7024g of Cu material, 7.6478g of Fe material, 8.0379g of Ni material and 3.8462g of Si material after ultrasonic treatment obtained in step 1;

3. Melting high-entropy alloys: ①Put 50g of titanium sponge into a smelting pool of a water-cooled copper mold, and then weigh the Al material, Co material, Cu material, Fe material, Ni material and Si material after ultrasonic treatment in step 2. The materials are placed in another smelting pool of the water-cooled copper mold. According to the melting point of each material, they are placed in order from low to high and from bottom to top. After the materials are placed, cover the furnace cover and tighten the knob of the sample chamber; ② pump the melting furnace Vacuum, when the vacuum degree is 1×10 ^-3 Pa, fill it with argon gas until the pressure is 1 atm; ③Repeat step ②5 times; ④Repeat the smelting of titanium sponge 4 times under the condition of smelting current of 300A, each time for 120s; ⑤ Under the condition that the smelting current is 300A, the Al material, Co material, Cu material, Fe material, Ni material and Si material after the ultrasonic treatment taken in step 2 in the smelting step ① were smelted for 120s to obtain an ingot; The ingot was turned over, and then smelted for 100s under the condition of a melting current of 300A; ⑦Repeat step ⑥6 times, and cool with the furnace to obtain an ellipsoidal AlCoCuFeNiSi high-entropy alloy.

The purity of the Al material, Co material, Cu material, Fe material, Ni material and Si material mentioned in step 1 are all ≥99.9%.

The Al material, the Co material, the Cu material, the Fe material, the Ni material and the Si material described in step 1 are all in the form of blocks.

Add acetone solution and ultrasonic cleaning as described in step 1. The amount of acetone solution is such that the Al material, Co material, Cu material, Fe material, Ni material and Si material are completely immersed.

Add absolute ethanol, ultrasonic cleaning, and the amount of acetone solution described in step 1 is such that the Al material, Co material, Cu material, Fe material, Ni material and Si material are completely immersed.

Place in a drying oven for drying as described in step 2, and the drying process is to dry at a temperature of 50° C. for 30 minutes.

(1) Cut a sample of Ф6mm×5mm from the AlCoCuFeNiSi high-entropy alloy ingot prepared from Test 1 by wire cutting, and use 80#, 120#, 200#, 400#, 600#, 800# in turn to cut the sample , 1000#, 1200#, 1500# and 2000# water sandpaper grinding to obtain the AlCoCuFeNiSi high-entropy alloy after grinding, and then use the X-ray diffractometer to carry out the phase composition of the AlCoCuFeNiSi high-entropy alloy sample after metallographic grinding For component analysis, the scan step length is 0.02s ^-1 , and the scan angle 2θ ranges from 20° to 100°; the test results are shown in Figure 1, which is the XRD pattern of the AlCoCuFeNiSi high-entropy alloy prepared in Experiment 1, in which "■ "Represents FCC, "●" represents BCC; It can be seen from Figure 1 that the AlCoCuFeNiSi high-entropy alloy prepared in Experiment 1 is composed of BCC and FCC solid solution, in which FCC is the main phase and BCC is the secondary phase.

Fig. 2 is the microstructure (X1000) photograph of the AlCoCuFeNiSi high-entropy alloy prepared by test one; Fig. 3 is the microstructure (X4000) photograph of the AlCoCuFeNiSi high-entropy alloy prepared by test one; Fig. 4 is the AlCoCuFeNiSi high-entropy alloy prepared by test one Alloy EDX analysis histogram.

It can be seen from Figure 2 that the actual average composition of the AlCoCuFeNiSi high-entropy alloy prepared in Experiment 1 deviates from the nominal composition, in which Al and Si elements are higher than the nominal composition, while Cu, Fe and Ni are lower than the nominal composition. The alloy has three phases in total, among which the dendritic structure is the BCC phase and the intergranular structure is the FCC phase.

Actual average composition mass percentage: Al: 18.4at.%, Co: 16.6at.%, Cu: 14.4at.%, Fe: 15.9at.%, Ni: 16.2at.%, Si: 18.5at.%.

In Fig. 3, 1 is a Cu/Al-rich phase, a Cu ₃ Al-like phase, 2 is a Cu-poor phase, and 3 is a dendritic phase whose composition is close to the nominal composition.

In Figure 4, 1 is a Cu/Al-rich phase, a Cu ₃ Al-like phase, 2 is a Cu-poor phase, and 3 is a dendrite phase whose composition is close to the nominal composition

(3) The AlCoCuFeNiSi high-entropy alloy prepared by Quanta200F electron microscope test 1 equipped with EDX system was used to analyze the chemical composition of each phase, and the EDX detection values of each element in each phase as shown in Table 1 were obtained.

Table 1 shows the chemical composition of each phase of AlCoCuFeNiSi high entropy alloy (at.%)

In Table 1, the dendrite DR-A is a dendrite whose composition is close to the nominal composition; the dendrite DR-B is a Cu-poor phase; the interdendritic ID is a Cu/Al-rich phase, a Cu ₃ Al-like phase.

(4) Using a Quanta200F electron microscope equipped with an EDX system to detect the surface distribution and segregation of each element on the AlCoCuFeNiSi high-entropy alloy prepared in Experiment 1, the Al elements, Co elements, Cu elements, Fe elements, and Ni elements in the AlCoCuFeNiSi high-entropy alloy were obtained. The surface distribution and segregation diagrams of elements and Si elements are shown in Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9 and Fig. 10.

(5) Cut out a sample of Ф6mm×5mm from the AlCoCuFeNiSi high-entropy alloy prepared in Test 1 by wire cutting, and use 80#, 120#, 200#, 400#, 600#, 800#, 1000# in turn to cut the sample , 1200#, 1500# and 2000# water sandpaper, and then use a polishing machine to polish, use HDX-1000TM Vickers microhardness to measure the microhardness of the polished AlCoCuFeNiSi high entropy alloy, the load loaded during the experiment 50g, hold for 10s; the polished AlCoCuFeNiSi high-entropy alloy randomly tests the data of 7 points, after removing the maximum and minimum values, the average value of the remaining 5 points is the microhardness of the AlCoCuFeNiSi high-entropy alloy prepared in Experiment 1, the test result The microhardness of the AlCoCuFeNiSi high-entropy alloy prepared for Test 1 was 688HV.

(6) Cut the AlCoCuFeNiSi high-entropy alloy prepared in Test 1 into 3 cylindrical samples of Ф4mm×6mm; carry out the compression test at room temperature on the Instron5569 universal electronic testing machine with a loading rate of 0.5mm/min, and draw the compressed data using Origin software Compressive true strain-true stress curve. The compression mechanical properties are listed in Table 2, and the compression curve is shown in Figure 11.

Table 2 Compressive mechanical properties and hardness values of AlCoCuFeNiSi high-entropy alloys

It can be seen from Table 2 and Figure 11 that the AlCoCuFeNiSi high-entropy alloy prepared in Experiment 1 has high hardness, high compressive yield strength, and fracture strength compared with traditional alloys. The yield strength is as high as 1781.6MPa, and the fracture strength is as high as 1895.2MPa. Its high hardness comes from the joint action of solid solution strengthening, precipitation strengthening and nano compound strengthening.

(6) Using a Quanta200F electron microscope equipped with an EDX system to observe the fracture properties of the AlCoCuFeNiSi high-entropy alloy prepared in Test 1, the compression fracture morphology diagrams are obtained as shown in Figure 12 and Figure 13, and Figure 13 is an enlarged view of a in Figure 12.

Claims (1)

1. a preparation method of AlCoCuFeNiSi high-entropy alloy, is characterized in that the method is carried out in the following steps: 1. Ultrasonic treatment: put Al material, Co material, Cu material, Fe material, Ni material and Si material in a container, then add acetone solution, ultrasonically clean for 25 minutes, remove oil and impurities attached to the surface, and obtain the impurity-removed Al material, Co material, Cu material, Fe material, Ni material and Si material, then put the Al material, Co material, Cu material, Fe material, Ni material and Si material in the container after removing impurities, add absolute ethanol Ultrasonic cleaning for 25 minutes, and then placed in a drying box for drying, to obtain Al material, Co material, Cu material, Fe material, Ni material and Si material after ultrasonic treatment; 2. Weighing materials: Weigh 3.6950g of Al material, 8.0707g of Co material, 8.7024g of Cu material, 7.6478g of Fe material, 8.0379g of Ni material and 3.8462g of Si material after ultrasonic treatment obtained in step 1; 3. Melting high-entropy alloys: ①Put 50g of titanium sponge into a smelting pool of a water-cooled copper mold, and then weigh the Al material, Co material, Cu material, Fe material, Ni material and Si material after ultrasonic treatment in step 2. The materials are placed in another smelting pool of the water-cooled copper mold. According to the melting point of each material, they are placed in order from low to high and from bottom to top. After the materials are placed, cover the furnace cover and tighten the knob of the sample chamber; ② pump the melting furnace Vacuum, when the vacuum degree is 1×10 ^-3 Pa, fill it with argon gas until the pressure is 1 atm; ③Repeat step ②5 times; ④Repeat the smelting of titanium sponge 4 times under the condition of smelting current of 300A, each time for 120s; ⑤ Under the condition that the smelting current is 300A, the Al material, Co material, Cu material, Fe material, Ni material and Si material after the ultrasonic treatment taken in step 2 in the smelting step ① were smelted for 120s to obtain an ingot; The ingot was turned over, and then smelted for 100s under the condition of a smelting current of 300A; ⑦Repeat step ⑥6 times, and cool with the furnace to obtain an AlCoCuFeNiSi high-entropy alloy with an ellipsoidal yield strength of 1781.6MPa, a fracture strength of 1895.2MPa, and a hardness of HV688; The purity of the Al material, Co material, Cu material, Fe material, Ni material and Si material described in step 1 are all ≥99.9%; The forms of the Al material, Co material, Cu material, Fe material, Ni material and Si material described in step 1 are all block; As described in step 1, add acetone solution, ultrasonic cleaning, the amount of acetone solution is such that the Al material, Co material, Cu material, Fe material, Ni material and Si material are completely immersed; Add absolute ethanol as described in step 1, ultrasonic cleaning, the amount of absolute ethanol is such that the Al material, Co material, Cu material, Fe material, Ni material and Si material are completely immersed; Place in a drying oven for drying as described in step 1, and the drying process is to dry at a temperature of 50° C. for 30 minutes.