A high entropy bulk amorphous alloy with obvious plasticity and excellent corrosion resistance and preparation method thereof

Abstract

The present invention discloses a high entropy bulk amorphous alloy with obvious plasticity and excellent corrosion resistance and a preparation method thereof. The structural formula of the alloy is Fe 35 Ni 20 Cr 20‑x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 (x=4, 8, 12at.%), where x represents the atomic percentage of Co in the alloy. The high entropy bulk amorphous alloy (HE-BMGs) was prepared by Fluxing and J-quenching techniques. When x=12at.%, the room temperature compression plasticity was 2.5%. The self-corrosion current density of existing HE-BMGs is on the order of 10 ‑9 A / cm 2 The overall corrosion resistance is much better than that of 316 stainless steel. This high entropy bulk amorphous alloy has excellent comprehensive properties and can be used under complex and harsh service conditions. It has potential value and significance for expanding the application range of high entropy bulk alloys.

Description

Technical Field

[0001] The present invention relates to the field of high entropy bulk amorphous alloys, and in particular to a high entropy bulk amorphous alloy with obvious plasticity and excellent corrosion resistance and a preparation method thereof. The high entropy bulk amorphous alloy has obvious room temperature compression plasticity and excellent corrosion resistance. Background Art

[0002] High entropy alloy (HEA) is a new type of alloy, which contains five or more main elements with equal or nearly equal atomic percentages ranging from 5 to 35 at.%. High entropy alloys with amorphous structures are called high entropy bulk amorphous alloys (HE-BMGs). Compared with traditional bulk amorphous alloys (BMGs), HEA has unique physical, mechanical, chemical and biomedical properties, and has attracted more and more attention from researchers.

[0003] With the continuous progress of science and technology and industrial production, the requirements for material performance are no longer limited to one aspect. When facing complex and harsh service environments, materials have higher requirements for their comprehensive performance. However, when most high-entropy bulk amorphous alloy materials show their excellent performance, some performance defects in themselves will limit their wide application as structural and functional materials in production and life. For example, Fe 20 Co 20 Ni 20 Cr 15 5P 10 B 10 It has good corrosion resistance, but its compression plasticity at room temperature is almost zero. FeCoNi(B,Si,P,C)HE-BMGs alloy has excellent soft magnetic properties, with a coercivity of only 1.1A / m, but its glass forming ability is low, and size limitations often reduce the magnetic properties of the final product. (Fe 1 / 3 Co 1 / 3 Ni 1 / 3 ) 80 (P 1 / 2 B 1 / 2 ) 20 The room temperature compression plasticity of HE-BMG is 4.4%, and its corrosion resistance is poor due to the lack of corrosion-resistant elements such as Cr and Mo. Therefore, it is particularly important in academic and engineering applications to develop high-entropy bulk amorphous alloys with comprehensive properties so that they can be used in complex and harsh environmental conditions. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a high entropy bulk amorphous alloy with obvious plasticity and excellent corrosion resistance and a preparation method. 35 Ni20 Cr 20- x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 A high entropy bulk amorphous alloy, wherein x is any value of 4 at.%, 8 at.%, or 12 at.%. The high entropy bulk amorphous alloy has obvious room temperature compression plasticity and excellent corrosion resistance, and its comprehensive performance can be used under complex and harsh conditions.

[0005] The technical solution of the present invention is:

[0006] A high entropy bulk amorphous alloy with obvious plasticity and excellent corrosion resistance and a preparation method thereof, wherein the structural formula is Fe 35 Ni 20 Cr 20-x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 , x is the atomic percentage of Co element in the alloy;

[0007] x is any value of 4 at.%, 8 at.%, or 12 at.%.

[0008] The Fe 35 Ni 20 Cr 20-x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 The alloy raw materials used for HE-BMGs are iron powder, iron phosphide, nickel powder, chromium powder, cobalt powder, molybdenum powder, carbon powder and boron powder; the purity of iron powder, iron phosphide, nickel powder, chromium powder, cobalt powder, molybdenum powder, carbon powder and boron powder are 99%, 99%, 99.8%, 99.99%, 99.8%, 99.9%, 99.999% and 99.9% respectively.

[0009] The high entropy bulk amorphous alloy with obvious plasticity and excellent corrosion resistance and the preparation method thereof mainly include the following steps:

[0010] (1) Preparation of a master alloy ingot: According to the percentage of each atom in the nominal composition of the high entropy bulk amorphous alloy, weigh 1 g of raw materials and put them into a quartz tube, then connect the quartz tube to a vacuum system, evacuate the tube, and introduce Ar gas for washing when the vacuum degree reaches about 50 Pa. After repeating the above washing process 4 times, use a torch to melt the raw materials of each component in the quartz tube into a composite ingot;

[0011] (2) transferring the alloy ingot prepared in step (1) into a purification medium containing molten B2O3 and performing a purification treatment for about 3 hours;

[0012] (3) The alloy ingot purified in step (2) is placed in a prefabricated special quartz tube and subjected to vacuum treatment. When the vacuum degree reaches about 50 Pa, Ar gas is introduced for gas washing. The above gas washing operation is repeated 4 times. After the gas washing is completed, the purified alloy ingot is heated to a molten state with a torch, and quickly inserted into a vertical sintering furnace, and then Ar gas is introduced to push the molten alloy ingot into the bottom of the quartz tube. After keeping warm for a certain period of time, it is taken out and quickly quenched in water.

[0013] The beneficial effects of the present invention are embodied in:

[0014] (1) Fe prepared by the present invention 35 Ni 20 Cr 20-x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 HE-BMGs, when x = 12 at.%, the room temperature compression plastic deformation is 2.5%;

[0015] (2) Fe prepared by the present invention 35 Ni 20 Cr 20-x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 HE-BMGs, x is any value among 4 at.%, 8 at.%, or 12 at.%, and the self-corrosion current density is of the order of 10 -9 A / cm 2 , the overall corrosion resistance is better than 316 stainless steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the XRD diagram of the high entropy bulk amorphous alloy prepared in Example 1-3.

[0017] Figure 2 1 is the compressive stress-strain curve of the high entropy bulk amorphous alloy prepared in Example 1-3.

[0018] Figure 3 The potentiodynamic polarization curves of the high entropy bulk amorphous alloys prepared in Examples 1-3 and Comparative Example 1 (316 stainless steel). DETAILED DESCRIPTION

[0019] Example 1-3: Fe35 Ni 20 Cr 20-x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 Preparation of HE-BMGs, x is any value among 4 at.%, 8 at.% or 12 at.%, that is, the structural formula of the alloy in Example 1 is Fe 35 Ni 20 Cr 16 Co4Mo5(P 0.6 C 0.2 B 0.2 ) 20 ; The structural formula of the alloy in Example 2 is Fe 35 Ni 20 Cr 12 Co8Mo5(P 0.6 C 0.2 B 0.2 ) 20 ; The structural formula of the alloy in Example 3 is Fe 35 Ni 20 Cr8Co 12 Mo5(P 0.6 C 0.2 B 0.2 ) 20 .

[0020] Step 1: Calculate the atomic percentage of each element in Examples 1-3 and weigh 1g of raw materials. Put the weighed raw materials into a quartz tube and connect it to a vacuum system for evacuation. When the vacuum reaches about 50Pa, introduce Ar gas for gas washing. Repeat the gas washing for 4 times. Finally, use a torch to melt the raw materials into alloy ingots.

[0021] Step 2: The smelted alloy ingot is placed into a quartz tube containing molten B2O3 and purified in a purification furnace at a temperature of about 1150°C for about 3 hours.

[0022] Step 3: Place the purified alloy ingot in step 2 in alcohol for ultrasonic cleaning for about 30 seconds, then take it out to dry and put it into a prefabricated special quartz tube for vacuuming. When the vacuum degree reaches about 50Pa, introduce Ar gas for gas washing. After repeating the gas washing operation 4 times, heat the small ball to a molten state with a torch, quickly insert it into a vertical sintering furnace, immediately open the vacuum control valve for vacuuming, and then introduce Ar gas to push the alloy small ball into the bottom of the quartz tube. After keeping warm for a certain period of time, take it out and quickly quench it in water.

[0023] Determination of properties of Examples 1-3 and Comparative Example 1.

[0024] The structure of Example 1-3 was characterized by X-ray diffraction. The test used Cu target Kα radiation, the power was 18 kW, and the scanning rate was 5° / min. The results are as follows: Figure 1 As shown, Example 1-3 has only one broad bun peak, which is a typical sign of an amorphous alloy, and it can be determined that it is an amorphous structure.

[0025] The room temperature compressive mechanical properties of Examples 1-3 with a diameter of 1 mm and a height-to-diameter ratio of 2:1 were measured using a universal mechanical testing machine (WANCE ETM 105D). The compressive strain rate was 4×10 -4 s -1 The stress-strain curve is as follows Figure 2 shown.

[0026] The corrosion resistance of Examples 1-3 and Comparative Example 1 (316 stainless steel) in 3.5wt.% NaCl solution in open air at 298K was measured using an electrochemical workstation (ZAHNER-IM6EX). The potentiodynamic polarization curves are shown in Figure 3 shown.

[0027] Comparative analysis.

[0028] like Figure 1 The critical dimensions corresponding to Examples 1-3 are Φ=2.5 mm, 3.5 mm, and 3.0 mm, respectively, indicating that with the addition of the Co element, the glass-forming ability first increases and then decreases.

[0029] like Figure 2 The stress-strain curves of Examples 1-3 are shown, indicating that with the increase of the Co element content, the plasticity of the existing HE-BMGs continues to increase, and the maximum plasticity of Example 3 is 2.5%.

[0030] like Figure 3 The potentiodynamic polarization curves of Examples 1-3 and Comparative Example 1 are shown. The corrosion resistance of Examples 1-3 is better than that of Comparative Example 1.

[0031] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high entropy bulk amorphous alloy with obvious plasticity and excellent corrosion resistance, characterized in that The structural formula of the alloy is Fe 35 Ni 20 Cr 20-x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 , where x is the atomic percentage of Co element in the alloy; x is any value of 4 at.%, 8 at.%, or 12 at.%.

2. A method for preparing a high entropy bulk amorphous alloy according to claim 1, characterized in that The following steps are involved: (1) Fe 35 Ni 20 Cr 20-x Co x Mo5(P 0.6 C 0.2 B 0.2 ) 20 The alloy raw materials used in HE-BMGs are iron powder, iron phosphide, nickel powder, chromium powder, cobalt powder, molybdenum powder, carbon powder and boron powder; the purity of iron powder, iron phosphide, nickel powder, chromium powder, cobalt powder, molybdenum powder, carbon powder and boron powder are 99%, 99%, 99.8%, 99.99%, 99.8%, 99.9%, 99.999% and 99.9% respectively; (2) calculating the amount of raw materials required for each component in the alloy chemical formula according to the total mass weighed as 1 g, and transferring the weighed raw materials of each component into a quartz tube; (3) Connecting the quartz tube in step (2) to a mechanical pump for vacuuming, and when the pressure in the quartz tube is less than 50 Pa, introducing Ar gas into the quartz tube for gas washing; after the above vacuuming and gas washing operations are repeated 4 times, the raw materials in the quartz tube are melted into alloy ingots using a torch; (4) placing the alloy ingot smelted in step (3) into a quartz tube containing molten purification medium B2O3 for purification; (5) The alloy ingot purified in step (4) is placed in a prefabricated special quartz tube, and a mechanical pump is connected to evacuate the tube. When the air pressure in the quartz tube is less than 50 Pa, Ar gas is introduced into the quartz tube for gas washing. After the above vacuuming and gas washing operations are repeated 4 times, the alloy ingot in the quartz tube is heated to a molten state with a torch, and then quickly inserted into a vertical sintering furnace. Ar gas is introduced to push the molten alloy ingot into the bottom of the quartz tube and keep it warm for a certain period of time, and finally quickly quenched into water.

3. The method for preparing a high entropy bulk amorphous alloy according to claim 2, characterized in that During the purification treatment in step (4), the temperature is controlled at 1150° C. and the purification treatment is carried out for 3 hours. To prevent the alloy ingot from being oxidized, vacuum is drawn throughout the purification process. Every 10 minutes for the first hour of the purification treatment, the quartz tube containing the alloy ingot is taken out of the purification furnace to observe whether there is any re-calendering phenomenon. The above operation is repeated every 30 minutes for the next two hours.

4. The method for preparing a high entropy bulk amorphous alloy according to claim 2, characterized in that In the step (5), the temperature of the vertical sintering furnace is set to 1290° C., and the holding time is 1 minute.

5. According to the method for preparing a high entropy bulk amorphous alloy according to claim 2, the special quartz tube used in step (5) consists of a thick tube with an inner diameter / outer diameter of 11 / 13 mm and a thin tube with an inner diameter of 1.0~3.5 mm and a wall thickness of 0.1~0.35 mm.

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