Iron-based medium-entropy alloy with high strength and plasticity in wide temperature range and preparation and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHENGZHOU UNIV
- Filing Date
- 2024-04-17
- Publication Date
- 2026-07-21
AI Technical Summary
Existing iron-based, nickel-based, and cobalt-based alloys cannot simultaneously meet the requirements of excellent strength, plasticity, and corrosion resistance at room temperature, liquid nitrogen temperature, and high temperature, which limits their application in high and low temperature engineering.
By optimizing the FeNiAlTi system by adding an appropriate amount of Cr, and combining vacuum arc melting, casting, rolling, homogenization treatment and aging treatment, a medium-entropy iron-based alloy was prepared. Its composition and processing technology were controlled to improve its mechanical properties and corrosion resistance at high and low temperatures.
The alloy exhibits excellent mechanical properties at 298K, 77K, and 973K, with significantly improved tensile yield strength and elongation. Its corrosion resistance is comparable to that of 304 stainless steel, while its cost is close to that of traditional steel, making it a promising candidate for a wide range of applications.
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Figure CN118547220B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of alloy technology, specifically to an iron-based medium-entropy alloy with high strength and ductility over a wide temperature range, and its preparation and application. Background Technology
[0002] With the development of science and engineering technology, the performance requirements for alloy materials are becoming increasingly stringent. For example, in addition to meeting the requirements for strength and plasticity, materials are also required to have corrosion resistance. Currently, the development of new corrosion-resistant alloys that exhibit excellent strength and plasticity at room temperature (298K), liquid nitrogen temperature (77K), and high temperature (973K) is of great significance for high and low temperature engineering applications, such as nitrogen storage tanks, liquefied natural gas pipelines, automotive turbochargers, rocket engines, and other aerospace fields. However, the performance of existing iron-based, nickel-based, and cobalt-based alloys is difficult to meet the above requirements, thus necessitating the development of new alloy materials.
[0003] High-entropy alloys refer to novel alloy systems comprising five or more components with equal or near-equal atomic ratios. Due to their significant cocktail effect, they readily exhibit excellent comprehensive properties, including superior mechanical properties and corrosion resistance, providing new alloy design ideas for novel high-performance structural materials. Currently, high-entropy alloys demonstrate excellent mechanical properties at room temperature; however, polycrystalline high-entropy alloys exhibit severe intergranular embrittlement at high temperatures, resulting in excessively low high-temperature tensile properties, which seriously hinders their large-scale application in high-temperature fields. Therefore, significant efforts have been made in recent years to expand the application range of high-entropy alloys, but the performance gap between existing high-entropy alloys and nickel-based superalloys used in general high-temperature applications remains substantial, making it difficult to meet actual production needs.
[0004] In recent years, alloys containing large amounts of inexpensive Fe, also known as iron-based medium-entropy alloys, have gradually attracted attention due to their good tensile strength and uniform ductility. The high Fe content effectively reduces the stability of the FCC phase, thus introducing a deformation-induced martensitic transformation effect into iron-based medium-entropy alloys.
[0005] Among the prior art known to the inventor, patent document CN116574979A describes two low-cost, high-strength, and ductile iron-based medium-entropy alloys. These two high-entropy alloys exhibit good strength and ductility at both room temperature (298K) and low temperature (77K), but do not address high-temperature performance or corrosion resistance. Another patent document CN117385256A describes a FeCoCrNi high-entropy alloy and its preparation method. The disclosed high-entropy alloy exhibits certain strength and ductility at high temperature (973K), but its yield strength at 973K is only 511MPa, and its elongation is less than 7%, requiring further improvement in strength and ductility.
[0006] The information disclosed in this background section is intended only to enhance the understanding of the background technology of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention
[0007] Based on their understanding of the mechanism of iron-based medium-entropy alloys and their long-term research experience, the inventors of this application have optimized the FeNiAlTi system, attempted to add Cr to it, and optimized the corrosion resistance, high-temperature mechanical properties, and low-temperature mechanical properties by reasonably controlling the Cr content. At the same time, they have overcome or balanced the adverse effects of Cr, and developed a corrosion-resistant medium-entropy alloy with excellent mechanical properties at both high and low temperatures.
[0008] According to one aspect of this disclosure, an iron-based medium-entropy alloy is provided, which, by atomic percentage, comprises the following elements: Fe 50.1%~57.2%, Ni 27.2%~31.0%, Al 5.1%~5.8%, Ti 2.6%~2.9%, Cr 3.0%~15.0%, trace elements 0~5%.
[0009] In some embodiments of this disclosure, the iron-based medium-entropy alloy is composed of the following elements: Fe 51.0%–56.9%, Ni 27.7%–30.9%, Al 5.2%–5.8%, Ti 2.6%–2.9%, Cr 3.5%–13.5%, trace elements 0–5%.
[0010] In some embodiments of this disclosure, the trace element is at least one of C, B, Cu, Mo, Ti, Nb, V, and Zr.
[0011] In some embodiments of this disclosure, the expression for the obtained iron-based medium-entropy alloy is Fe. 56.6 Ni 30.7 Al 5.8 Ti 2.9 Cr 4.0 Fe 54.3 Ni 29.4 Al 5.5 Ti 2.8 Cr 8.0 or Fe 51.3 Ni 27.8 Al 5.2 Ti 2.6 Cr 13.0 .
[0012] According to another aspect of this disclosure, a method for preparing an iron-based medium-entropy alloy is provided, mainly comprising the following steps: (1) Alloy smelting raw materials are prepared according to the above atomic percentage, mixed and then vacuum arc melting is carried out to obtain alloy liquid; (2) The molten alloy is drawn into a copper mold to obtain an alloy ingot; (3) The alloy ingot is rolled to 14% to 16% of its original thickness to obtain an alloy plate; (4) The alloy plate is homogenized at 1373K for 1 to 3 hours, and then water-cooled; (5) After water cooling, the alloy plate is aged at 973K for 45-50 hours, and then water quenched to obtain the iron-based medium entropy alloy.
[0013] According to another aspect of this disclosure, the iron-based medium-entropy alloy can be used in high-temperature or low-temperature engineering, such as in the manufacture of equipment or components for nitrogen storage tanks, liquefied natural gas pipelines, automotive turbochargers, and rocket engines.
[0014] One or more technical solutions provided in the embodiments of this application have at least one of the following technical effects or advantages: 1. Based on the FeNiAlTi system, with the addition of an appropriate amount of Cr, a corrosion-resistant medium-entropy alloy with excellent mechanical properties (excellent strength and uniform elongation) at both high and low temperatures was developed. Mechanical property tests show that at room temperature (298K), the tensile yield strength of this alloy is between 760 MPa and 800 MPa, the ultimate tensile strength is between 1130 MPa and 1370 MPa, and the fracture strain is between 12% and 34%. At low temperature (77K), the tensile yield strength is between 900 MPa and 960 MPa, the ultimate tensile strength is between 1280 MPa and 1520 MPa, and the fracture strain is between 16% and 52%. At high temperature (973K), the tensile yield strength is between 710 MPa and 740 MPa, the ultimate tensile strength is approximately between 770 MPa and 800 MPa, and the fracture strain is between 32% and 34%.
[0015] 2. Compared with Cr-free iron-based medium-entropy alloys and 304 stainless steel, the iron-based medium-entropy alloy of this application not only has superior strength and plasticity at low temperature, room temperature and high temperature, but also has corrosion resistance exceeding that of traditional 304 stainless steel.
[0016] 3. The alloy of this application has raw material prices comparable to traditional steel and a wide range of compositional redundancy, and has great application potential. Attached Figure Description
[0017] Figure 1 This is a tensile curve diagram of high temperature (973K), room temperature (298K), and low temperature (77K) in Embodiment 1 of this application.
[0018] Figure 2 This is a tensile curve diagram of high temperature (973K), room temperature (298K), and low temperature (77K) in Example 2 of this application.
[0019] Figure 3 This is a tensile curve diagram of high temperature (973K), room temperature (298K), and low temperature (77K) in Example 3 of this application.
[0020] Figure 4 The tensile curves for high temperature (973K), room temperature (298K), and low temperature (77K) in the comparative examples of this application are shown.
[0021] Figure 5 This is a graph showing the product of yield strength and elongation for Embodiments 1, 2, 3 and the comparative example of this application.
[0022] Figure 6 The figures show the room temperature polarization curves for each embodiment and comparative example of this application. Detailed Implementation
[0023] The present application will now be described in further detail with reference to the accompanying drawings, embodiments, and comparative examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.
[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.
[0025] Unless otherwise specified, the instruments and equipment involved in the following embodiments are all conventional instruments and equipment; the raw materials involved are all commercially available conventional raw materials; and the detection, testing, and preparation methods involved are all conventional methods unless otherwise specified.
[0026] Example 1: Iron-based medium-entropy alloy Fe 56.6 Ni 30.7 Al 5.8 Ti 2.9 Cr 4.0 Preparation Using elements with a purity greater than 99.9 wt% as raw materials, Fe with a nominal composition was prepared by arc melting in an Ar atmosphere. 56.6 Ni 30.7 Al 5.8 Ti 2.9 Cr 4.0 Alloy ingots of (atomic percentage). All ingots were remelted at least 5 times under electromagnetic stirring to ensure homogeneity, and then suction-cast to 10×10×40 mm. 3The alloy ingot was obtained from a copper mold. The alloy ingot was cold-rolled from 10 mm to about 1.5 mm. The rolled sheet was homogenized at 1373 K for 2 hours and then water-cooled.
[0027] Flat specimens in the shape of a dog's bone, measuring 10 mm × 2.5 mm × 1.5 mm, were cut from a thin sheet. The samples were then aged at 973 K for 47 hours, followed by water quenching. Tensile tests were conducted at 77 K, 298 K, and 973 K using a screw-driven Suns UTM 5105 testing machine at a crosshead speed of 0.5 mm / min. For ease of description, the sample prepared in Example 1 is named Cr4.
[0028] Example 2: Iron-based medium-entropy alloy Fe 54.3 Ni 29.4 Al 5.5 Ti 2.8 Cr 8.0 Preparation Using elements with a purity greater than 99.9 wt% as raw materials, Fe with a nominal composition was prepared by arc melting in an Ar atmosphere. 54.3 Ni 29.4 Al 5.5 Ti 2.8 Cr 8.0 Alloy ingots were remelted at least five times under electromagnetic stirring to ensure homogeneity, and then suction-cast to a size of 10×10×40 mm. 3 The alloy ingot was obtained from a copper mold. The alloy ingot was cold-rolled from 10 mm to about 1.5 mm. The rolled sheet was homogenized at 1373 K for 2 hours and then water-cooled.
[0029] Flat specimens in the shape of a dog's bone, measuring 10 mm × 2.5 mm × 1.5 mm, were cut from a thin sheet. The samples were then aged at 973 K for 47 hours, followed by water quenching. Tensile tests were conducted at 77 K, 298 K, and 973 K using a screw-driven Suns UTM 5105 testing machine at a crosshead speed of 0.5 mm / min. For ease of description, the sample prepared in Example 2 is named Cr8.
[0030] Example 3: Iron-based medium-entropy alloy Fe 51.3 Ni 27.8 Al 5.2 Ti 2.6 Cr 13.0 Preparation Using elements with a purity greater than 99.9 wt% as raw materials, Fe with a nominal composition was prepared by arc melting in an Ar atmosphere. 51.3 Ni 27.8 Al5.2 Ti 2.6 Cr 13.0 Alloy ingots were remelted at least five times under electromagnetic stirring to ensure homogeneity, and then suction-cast to a size of 10×10×40 mm. 3 The alloy ingot was obtained from a copper mold. The alloy ingot was cold-rolled from 10 mm to about 1.5 mm. The rolled sheet was homogenized at 1373 K for 2 hours and then water-cooled.
[0031] Flat specimens in the shape of a dog's bone, measuring 10 mm × 2.5 mm × 1.5 mm, were cut from a thin sheet. The samples were then aged at 973 K for 47 hours, followed by water quenching. Tensile tests were performed at 77 K, 298 K, and 973 K using a screw-driven Suns UTM 5105 testing machine at a crosshead speed of 0.5 mm / min. For ease of description, the sample prepared in Example 3 is named Cr13.
[0032] Comparative example, medium-entropy alloy Fe 59.0 Ni 32.0 Al 6.0 Ti 3.0 Preparation Using elements with a purity greater than 99.9 wt% as raw materials, Fe with a nominal composition was prepared by arc melting in an Ar atmosphere. 59.0 Ni 32.0 Al 6.0 Ti 3.0 Alloy ingots were remelted at least five times under electromagnetic stirring to ensure uniformity, and finally drop-cast to a size of 10×10×40 mm. 3 In a copper mold, the steel ingot is cold-rolled from 10 mm to approximately 1.5 mm. The rolled sheet is then homogenized at 1373 K for 2 hours and subsequently water-cooled.
[0033] Flat specimens in the shape of a dog's bone, measuring 10 mm × 2.5 mm × 1.5 mm, were cut from a thin sheet. The specimens were then aged at 973 K for 47 h, followed by water quenching. Tensile tests were conducted at 77 K, 298 K, and 973 K using a screw-driven Suns UTM 5105 testing machine at a crosshead speed of 0.5 mm / min. For ease of description, the sample prepared using this comparative example is named Cr0.
[0034] The tensile stress-strain curves of the alloys in Examples 1, 2, 3 and the comparative examples at room temperature (298 K), liquid nitrogen temperature (77 K), and high temperature (973 K) are shown below. Figure 1 , Figure 2 , Figure 3 and Figure 4As shown in Table 1, the yield strength, tensile strength, and uniform elongation are as follows.
[0035] Table 1. Yield strength, tensile strength, and uniform elongation of each alloy .
[0036] Figure 5 This is a comparison graph showing the product of yield strength and elongation for Examples 1, 2, 3, and the comparative example. Figure 1-5 As shown in Table 1, the medium-entropy alloys provided in Examples 1, 2, and 3 all exhibit high yield strength, tensile strength, and uniform elongation at 77 K, 298 K, and 973 K, as well as an excellent product of yield strength and elongation.
[0037] like Figure 5 As shown, based on atomic percentages, when the percentage of Cr is between 3% and 15%, the compositions of other elements are Fe: 50.1%–57.2%, Ni: 27.2%–31.0%, Al: 5.1%–5.8%, and Ti: 2.6%–2.9%. The product of the yield strength and elongation of the sample alloy at room temperature (298K) and high temperature (973K) is above 20 GPa*%, indicating good mechanical properties.
[0038] Figure 6 The graphs show the polarization curves of Examples 1, 2, 3, the comparative example, and 304 stainless steel at room temperature. Figure 6 It is evident that Examples 1, 2, and 3 all exhibit significant passivation zones, and the width of these passivation zones is significantly greater than that of the comparative examples, indicating that the alloy samples of this invention possess excellent corrosion resistance. In particular, the passivation zones of Cr8 and Cr13 are significantly wider than those of commonly used 304 stainless steel, demonstrating that Cr8 and Cr13 exhibit superior corrosion resistance.
[0039] This application aims to develop a corrosion-resistant medium-entropy alloy with excellent strength and ductility at low, room, and high temperatures. A novel medium-entropy alloy with high strength and ductility and extremely low raw material costs has been prepared. This alloy exhibits excellent strength and uniform elongation at 298 K, 77 K, and 973 K. Comparisons between this invention and chromium-free alloys and 304 stainless steel show that it not only possesses superior strength and ductility at low, room, and high temperatures, but also corrosion resistance comparable to traditional 304 stainless steel. Furthermore, due to its raw material price comparable to traditional steel and its wide compositional redundancy, it has great application potential.
[0040] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.
Claims
1. A high-strength, high-ductility iron-based medium-entropy alloy with a wide temperature range, characterized in that, It is composed of the following elements by atomic percentage: Fe 50.1%~57.2%, Ni 27.2%~31.0%, Al 5.1%~5.8%, Ti 2.6%~2.9%, Cr 3.5%~15.0%.
2. The iron-based medium-entropy alloy according to claim 1, characterized in that, It consists of the following elements: Fe 51.0%~56.9%, Ni 27.7%~30.9%, Al 5.2%~5.8%, Ti 2.6%~2.9%, Cr 3.5%~13.5%.
3. The iron-based medium-entropy alloy according to claim 1, characterized in that, Its alloy formula is Fe 56.6 Ni 30.7 Al 5.8 Ti 2.9 Cr 4.0 or Fe 54.3 Ni 29.4 Al 5.5 Ti 2.8 Cr 8.0 .
4. A method for preparing an iron-based medium-entropy alloy, characterized in that, Includes the following steps: (1) Alloy smelting raw materials are prepared according to the atomic percentages described in claim 1, and then mixed and vacuum arc smelted to obtain alloy liquid; (2) The molten alloy is drawn into a copper mold to obtain an alloy ingot; (3) The alloy ingot is rolled to 14% to 16% of its original thickness to obtain an alloy plate; (4) The alloy plate is homogenized at 1373K for 1 to 3 hours, and then water-cooled; (5) After water cooling, the alloy plate is aged at 973K for 45-50 hours, and then water quenched to obtain the iron-based medium entropy alloy.
5. The application of the iron-based medium-entropy alloy of claim 1 in high-temperature or low-temperature engineering.