According to reports, researchers at the University of Virginia have developed a new high-temperature, low-cost alloy by combining nickel powder and graphene flakes. This modern metal matrix composite material can maintain integrity at 1000 degrees Celsius or will be widely used in industrial fields.
Such lightweight materials are called "graphene superalloys" (graphene superalloy). Because of the use of lightweight graphene materials, it is lighter than other nickel superalloys but more reliable and more durable than different metal mixtures. Chris Li, a professor at the School of Mechanical and Aerospace Engineering who led the research, said: "This material is very light, and the perfect combination of strength and toughness may make it an ideal material for key components such as fuel nozzles for natural gas engines."
Superalloys have critical applications in many fields, and they are also essential for new and renewable energy technologies, such as biomass "green" energy, biomass gasification, carbon capture, and storage bioenergy, concentrated solar energy, and solids Oxide fuel cells, etc. They also play an essential role in many other critical technical fields such as jet engines, petrochemistry, and material processing. At high temperatures, the alloy reacts violently with its environment, causing the material to fail due to corrosion. To prevent corrosion, the surface of the superalloy is usually coated with a protective layer of aluminum oxide or chromium oxide. This protective layer plays a decisive role in preventing metal corrosion. Researchers at the Chalmers University of Technology in Sweden have made a systematic study of superalloys, explained the principle of the formation of superalloy protective layer and the reasons for its corrosion resistance, and proposed a new method to improve the performance of the alloy.
The researchers first explained two classic problems in the field of superalloys. The effect of "active elements" (usually yttrium and zirconium) that are ubiquitous in superalloys; about the role of water vapor in corrosion protection. The researchers showed the connection between these two factors and demonstrated how the active elements in the alloy promote the growth of the protective layer of alumina. It is because of the presence of these dynamic elements that the protective layer of alumina grows inward, Thereby promoting the transfer of water vapor from the surrounding environment to the alloy substrate. The interaction between the active element and water promotes the formation of a metastable "chaotic" nano-alumina layer.
When designing materials, researchers took inspiration from mother-of-pearl shells, which have a layer-by-layer structure. Mother-of-pearl is composed of hexagonal aragonite flakes. Its strength and toughness are scarce in engineering materials. When manufacturing most composite materials, the combination of the two alloys will cause most composite materials to lose flexibility or toughness. However, with aragonite-like structures, the strength of graphene and nickel composites can be increased by 73%, and the tensile capacity is only reduced by 28%. This composite material can maintain high hardness even at a high temperature of 1000 degrees Celsius.
Replacing battery and engine materials with graphene reinforced plastics helps reduce energy consumption. But because graphene is too expensive to achieve. Because in large-scale applications, cost needs to be considered. The price will always come first. If the value of graphene cannot be reduced, graphene cannot be used in large quantities.
Researchers expect graphene to be used to improve standard technology on a smaller, lower-cost scale in the next five years or so. For example, it can be used for 3D printing; it may also be used to manufacture flexible screens or even flexible batteries for mobile phones.
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