Patent Application
20250129456
As the development of modem society is driven by energy, the world's energy consumption in 2020 reached an increase of 172.8% over the energy consumption in 1970. Meanwhile, the usage of conventional fossil fuels has resulted in massive carbon emissions into the atmosphere, raising concerns about global warming. Thus, in order to meet future energy needs, countries must focus on the development of renewable and environmentally friendly energy. The reduction of weight in structural materials, such as aluminum-based and iron-based alloys offers a huge potential for lowering energy consumption and reducing environmental impact.
A novel category of alloys, named as High Entropy Alloys (“HEA”), broke the design rules of traditional alloys (e.g., stainless steel) and gave rise to a new alloy system where five or more elements having an atomic percentage between 5 and 35% are combined to produce a single-phase alloy. HEA exhibit an exceptional combination of properties, such as combined strength-ductility performance, improved fatigue resistance, high fracture toughness, and high thermal stability.
These exemplary properties enable the HEAs to have a high potential for a wide range of energy applications. With a hoisted strength-to-weight ratio, good oxidation resistance, fatigue resistance, hot consumption opposition, elevated temperature strength, lightweight, wear and creep resistance, HEAs are excellent materials for compressors, combustion chambers, exhaust nozzle, and gas turbine case applications within the gas turbine engine. They also represent a desirable option for designing tools, molds, dies, mechanical parts, and furnace parts requiring the properties of high strength, thermal stability, and wear and oxidation resistance. HEAs with anticorrosive and high-strength characteristics can be used in military applications such as vehicle armor, aircraft gas turbine engines, and engine parts, including turbine blades, disks, shafts, compressor wheels, and engine bolts. HEAs with anticorrosive and high-strength characteristics can be used in marine applications for piping and pump components requiring excellent corrosion resistance.
In the aerospace industry, materials used as modem engine components must be able to withstand extreme operating temperatures, creep, fatigue crack growth, and translational movements of parts at high speed. Therefore, the parts produced must be lightweight and have good elevated-temperature strength, fatigue, and resistance to chemical degradation, wear, and oxidation resistance. Hence, HEAs are considered potential solutions for several functional and structural applications in the aerospace industry. Moreover, using these lightweight HEAs for the body of plans is expected to reduce fuel consumption significantly. Among the multiple scenarios of hydrogen energy, i.e., production, storage, transportation, and utilization, efficient, safe, and inexpensive storage is often the bottleneck hindering its commercialization. The introduction of HEAs greatly expands the design space of alloy materials, including those for hydrogen storage. With lightweight, excellent mechanical, electrical, electrochemical, and anticorrosion properties, high entropy alloys are alternative alloys for reducing the weight and/or consumed power for a wide range of applications, including automobiles, constructions, transportation, packaging, architectural, consumer electronics, infrastructure and much more.
While many HEAs have been found to exhibit unique features, only a tiny percentage of the whole composition space has been examined. Despite making much progress, the improvements in the strength-ductility combination are somehow limited. Moreover, many of the reported HEAs that show a relatively good combination of properties contain expensive, rare earth elements such as Zr, Ta, Mo, Sc, and Nb. As such, the use of rare earth elements can cause significant barriers to large-scale manufacturing and utilization of such HEAs.
Thus, there exists a need for cost-effective HEA compositions exhibiting mechanical and corrosion properties that are significantly outperforming conventional alloys (e.g., stainless steel, nickel super alloys, titanium alloys), exceeding the properties of previously reported HEA, with no expensive rare earth elements.
According to one non-limiting aspect of the present disclosure, an example embodiment of a HEA composition is provided. In one embodiment, the composition includes iron (Fe) in a range of 0-30% by weight, nickel (Ni) in a range of 20-55% by weight, cobalt (Co) in a range of 5-45% by weight, chromium (Cr) in a range of 0-40% by weight, aluminum (Al) in a range of 0-20% by weight, manganese (Mn) in a range of 0-5% by weight, and niobium in a range of 0-10% by weight.
In another embodiment, the composition includes iron (Fe) in a range of 0-25% by atomic ratio, nickel (Ni) in a range of 30-60% by atomic ratio, cobalt (Co) in a range of 5-45% by atomic ratio, chromium (Cr) in a range of 0-40% by atomic ratio, aluminum (Al) in a range of 0-20% by atomic ratio, manganese (Mn) in a range of 0-10% by atomic ratio, and niobium in a range of 0-10% by atomic ratio.
Additional features and advantages are described herein, and will be apparent from the following Detailed Description and the figures.
Features and advantages of the present disclosure, including a high entropy alloy composition and methods of manufacturing such composition described herein may be better understood by reference to the accompanying drawings in which:
The reader will appreciate the foregoing details, as with others, upon considering the following detailed description of certain non-limiting embodiments of the present disclosure.
The present disclosure is generally related to a high entropy alloy composition and methods of manufacturing such composition.
The ranges of embodiments for a high entropy alloy compositions by weight percentage are shown in
The HEA compositions as shown in
In addition, as presented, most reported, previously known HEA compositions have equimolar ratios for most of the elements, and studies focus on altering the amount of one or two elements (ex: AlCoCrFeNi2.1 have aluminum, cobalt, chromium, and iron in the same ratios, while nickel has higher amount). The present disclosure, however, is based on optimized percentages of every single element (ex: Fe5Ni50Co10Cr25Al10), which resulted in producing a combination of high tensile strength and high ductility (up to 70%, which has not been reported yet in these elements), as shown in
Moreover, some other studies on HEAs with different elements reported a relatively good combination of tensile strength and ductility, but have utilized costly elements such as molybdenum, zirconium, hafnium, tantalum, and tungsten, however, the reported data, such as that shown in
In addition to the produced combination of high ductility and tensile strength, the present disclosure has exceptional corrosion resistance properties unknown in the prior art. Even though only a few reports on the corrosion behavior of HEAs are available, most reveal a corrosion rate ranging between 0.31-1000 mpy in 3.5 wt % NaCl solution. The present disclosure, astonishingly, has shown an extremely slow corrosion rate of about 10×10-6 mpy (indicating that the material barely corrodes at all), which is thus superior to all previously reported corrosion behaviors.
The resulting HEAs own a combination of high-yield tensile strength (1000-1800 MPa) and high ductility (up to 70%). Moreover, a corrosion resistance of up to 10-6 mpy was recorded. These extraordinary properties, which have never been observed in any commercial alloy generally, or HEAs specifically, are promising for enhancing fuel efficiency and reducing environmental burdens. Applications for these HEAs include military, aerospace, industry, automobiles, construction, transportation, packaging, and architectural infrastructure.
To manufacture an HEA, raw elements must be obtained. In one such embodiments, the starting materials may be an aluminum slug having a purity of 99.99%, a cobalt slug having a purity of 99.95%, chromium chips having a purity of 99.5%, iron pieces having a purity of 99.99%, a nickel slug having a purity of 99.98%, nickel wire having a purity of 99.95%, and niobium pieces having a purity of 99.9%. The aluminum slug may be obtained from Alfa Aesar and have dimensions of 3.175×3.175 mm. The cobalt slug may be obtained from Beantown Chemical and have dimensions of 3.175×3.175 mm. The chromium chips may be obtained from Sigma-Aldrich and be 2 mm thick. The iron pieces may be obtained from Beantown Chemical and have dimensions of 3.2-6.4 mm. The nickel slug may be obtained from Nanoshell and have dimensions of 3.175×6.35 mm. The nickel wire may be obtained from Beantown Chemical and have dimensions of 1×2 mm. The niobium pieces may be obtained from ESPI Metals and have dimensions of 3.2-6.4 mm. It will be appreciated that the amounts, purities, dimensions, and sources of the materials obtained may differ in other embodiments.
To manufacture the HEA compositions, the high-purity elements are weighted according to the specified compositions under ultra-high purity argon atmosphere (where O2<0.5 ppm) of an mBRAUN-LABstar glovebox. The elements are then placed inside the copper stage of the arc melting device such as one provided by Edmund Buhler GmbH, MAM1, and arranged according to their melting point. The sample chamber is evacuated and refilled with argon three times in order to ensure an oxygen-free atmosphere. After refilling the chamber with argon (pressure of −0.7 bars), a titanium piece is melted a couple of times to reduce the effect of humidity and possible oxidation. The weighted composition is arc melted and the current was increased to 5 A until all the elements combined together. The casted alloy is then flipped and remelted multiple times to ensure homogeneous mixing. The final ingot is annealed at 1000° C. via a tube furnace (such as GSL-1500X-RTP50) under mixed gas (2% hydrogen, 98% argon), then air cooled.
Further treatments are then carried out based on the desired strength-ductility-corrosion resistance properties. Post-treatments include cold rolling (from 50%-90% reduction), and aging at different temperatures [e.g., 600, 700, 800, 900, 950, 1000° C.] for 1 hour under mixed gas (2% hydrogen, 98% argon).
Optimized thermomechanical treatments may also be performed on the high entropy alloy. These thermomechanical treatments are different per composition and may include any of the following: annealing of the HEA at temperatures from 1000° C. to 1200° C. in an inert atmosphere for up to 2 hours; air cooling the HEA to room temperature; cold rolling of the HEA for a range from 40% to 90% reduction; aging of the HEA at temperatures ranging from 600° C. to 950° C. for one hour; and quenching the HEA to room temperature. Some compositions may require a second aging step at 700° C.-800° C. for a range of aging time of 6-8 hours.
Additionally, the composition of the HEA may be changed by changing the processing conditions (such as temperature of annealing, cooling rate) or post-processing treatments (aging temperatures, rolling temperature, further treatments, precipitation hardening processes, etc.). Altering the techniques used to prepare the HEA may also alter the HEA composition. This may include using ball milling or laser cladding materials. It will be appreciated that the methods for manufacturing and thermomechanical treatments listed in the present disclosure are purely exemplary and other methods for manufacturing and thermomechanical treatments may exist.
It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
The present application claims the benefit of U.S. Provisional Application No. 63/544,828 filed Oct. 19, 2023, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63544828 | Oct 2023 | US |
