Lighter vehicles can travel farther on less energy, driving demand for lighter automotive components. High-performance aluminum alloys, such as alloy 7075, are among the lightest and strongest options, but they require energy-intensive production that raises costs and therefore limits their use.
Research from the Pacific Northwest National Laboratory (PNNL) cuts that energy in half with a more efficient process to manufacture high-performance aluminum components. With support from the Department of Energy's Advanced Manufacturing Office, researchers determined that the Shear Assisted Processing and Extrusion (ShAPE) technology can eliminate heat treatment steps in the production process, resulting in significant energy savings and reduced emissions. ShAPE is a green, affordable manufacturing approach that enables broad use of high-performance aluminum alloys in automotive applications.
Much like baking a cake, metals manufacturing relies on well-mixed ingredients and a lot of heat. Conventional metal production uses heat to melt individual metals and alloying elements together—like aluminum, copper, or magnesium—to create alloys that are lighter, stronger, or easier to form. If these elements aren't well-mixed, cracks and fractures can form during processing that compromise the properties of the final product—as an undermixed, lumpy cake batter will result in a crumbling, disastrous cake. In metals production, heat is used to ensure that individual metal elements in an alloy are well-mixed during a step called homogenization.
During homogenization, large metal castings called billets are heated to nearly 500 degrees Celsius—about 900 degrees Fahrenheit—for up to 24 hours. This heat treatment step dissolves alloy aggregates—akin to lumps in the cake batter—in the billet to ensure that all metal elements are evenly distributed or homogenized. This improves the performance of the final product. After homogenization, the metal rods undergo further heating and forming in a step called extrusion.
"Homogenization is the biggest energy-consuming step in the entire metals extrusion process," said Scott Whalen, PNNL chief materials scientist and co-developer of ShAPE.
Shear Assisted Processing and Extrusion (ShAPE™), developed by researchers at Pacific Northwest National Laboratory, improves the energy efficiency of producing extruded high-performance aluminum alloys. Credit: Composite image by Cortland Johnson | Pacific Northwest National LaboratoryThe ShAPE machine eliminates the need for separate homogenization and extrusion steps by combining heating and deformation—the change in the shape of the metal itself. In the ShAPE machine, the metal billet is simultaneously pushed through a small opening in a die which rotates. Together, the rotational movement and deformation thoroughly mixes the metal elements as they are being extruded. Essentially, the ShAPE process homogenizes the metal billet in a few seconds, immediately before it is extruded. This eliminates the need for a day-long, pre-heating homogenization step and means that no additional energy is used to heat the billet during extrusion. Together, this results in an energy savings of up to 50 percent using ShAPE.
Not only is ShAPE a more energy efficient and quicker process, but it also improves how well the individual alloying elements are mixed, leading to a better final product. Like lumpy batter can ruin a cake, the final product in extrusion manufacturing often performs better when the elements are well-mixed. Performance testing showed that components made of aluminum alloys processed with ShAPE exceeded current American Society for Testing and Materials standards for strength and elongation.
"We took a closer look using an electron microscope and saw that ShAPE breaks apart the alloy aggregates and dissolves them into the aluminum matrix prior to extrusion, making it more extrudable," said Tianhao Wang, PNNL materials scientist and lead author on the recent publication in Materials and Design. "This translates to better performance—our aluminum 7075 alloys are stronger and stretch farther before breaking."
Aluminum alloys are valued in the automotive and aerospace industries because they are strong and lightweight. The most high-performance aluminum alloys are time- and energy-intensive to manufacture, pricing them out of many markets, like applications in passenger vehicles. The ShAPE process removes a major hurdle in the production of high-performance aluminum alloys by dramatically reducing energy consumption and greenhouse gas emissions during manufacturing.
"This is an important step in unlocking the potential of next-generation metals manufacturing to produce better, cheaper, greener products for the future," said Whalen.
More information: Tianhao Wang et al, Extrusion of Unhomogenized Castings of 7075 Aluminum via ShAPE, Materials & Design (2021). DOI: 10.1016/j.matdes.2021.110374
Sertac Akar et al, Techno-Economic Analysis for Shear Assisted Processing and Extrusion (ShAPE) of High Strength Aluminum Alloys, (2022). DOI: 10.2172/1846614
Citation: Aluminum alloy manufacturing now 50% more energy efficient (2022, July 20) retrieved 2 April 2024 from https://phys.org/news/2022-07-aluminum-alloy-energy-efficient.html
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There are many raw materials that get used for industrial purposes, such as steel, copper, zinc, lead, nickel and plastics, but aluminum is one of the most popular. The Dustin Hoffman film “The Graduate” from 1967 had the famous quote about there being a great future in plastics which probably should have been said about Aluminum since it is second only to steel in its overall industrial consumption. Aluminum possesses several unique properties that make it very versatile and sought after for everything from building aircraft to making soda cans. The fact that this metal is recyclable means that it will probably become even more popular in all uses as time goes on and other resources become more limited.
Aluminum is an extremely light metal, but still very strong. It is roughly one third of the weight of steel and less than one fourth of the weight of lead. This makes it extremely useful for many applications, especially in the transportation industry. Aluminum plate suppliers are constantly filling orders for those who build airplanes, boats, cars and trucks, since the lighter relative weight (or density) of aluminum compared to steel allows these vehicles to go faster, be more fuel efficient, carry more payload, float and fly.
Aluminum is a very versatile metal, which allows it to be manufactured into many different forms, such as aluminum plate, bars, sheets or extrude shapes, Aluminum is created in a variety of different alloys and each specific alloy offers different benefits to manufacturing. For instance, 6061 aluminum plate or 7075 aluminum plate, are good for machined parts, while alloys like 5052 and 3003 are more pliable and work best when rolled or bent. In the hands of a skilled craftsman with the proper precision equipment, aluminum can be cut or formed to just about any shape or size. Aluminum also has the ability to be rolled very thin, which allows it to be used for things like foil and soda cans.
Aluminum conducts electricity very well. This property makes the metal very useful in the construction of electronics and circuits. It also has fairly good thermal conductivity, allowing it to transfer most of the heat or cold it receives evenly across its surface. This makes aluminum a very popular choice for cookware as well as heating and air conditioning equipment.
The use of aluminum just in a standard home is extensive. You can find this material present in window frames, cooking supplies, toasters, framework, door knobs, exercise equipment, golf clubs, and more.
Aluminum is used extensively in the construction industry due to its great versatility. The material can be cut, welded, and molded to produce a vast array of components and products. Construction applications also benefit due to its lightweight characteristic. This makes it a less expensive option than other metals. Aluminum in manufactured for various construction elements, such as doors, railings, skylights, wiring, and shutters, among others.
Extruded aluminum can be used in office furniture framing of cubicles and to create frameworks that are often used for displays at tradeshows or in retail shops.
The defense industry also makes use of aluminum extrusions. The material is ideal for these applications due to its low weight and high strength. The applications including landing mats, military ships, all-terrain vehicles, and tent structures. Pretty much anything that will lighten the load for our troops to carry or transport is designed out of Aluminum.
Copper has about one-half times the electrical conductivity of aluminum, making it better in many applications, but copper has its limitations in strength. This makes aluminum a great option for use in power system applications. Applications that involve the mounting of solar panels also make use of aluminum due to its low maintenance requirement and lightweight property. Some power structures benefit from the use of aluminum due to its ability to support snow loads and high wind loads.
The transportation industry also benefits from the manufacturing of aluminum. A primary benefit to this industry is its high strength-to-weight ratio, a great asset in the building of aircraft, cars, trains, and boats. Aluminum alloys can achieve sufficient strength for certain applications in the transportation sector that make it a highly advantageous option. Its strength helps it withstand loading and its low weight can increase the energy efficiency of operations in which it is used.
The packaging industry also makes use of aluminum extensively. Aluminum is impermeable and it helps keep food clean and protected from harmful environmental elements. Aluminum oxide is not a destructive element and aluminum itself is highly resistant to corrosion.
Aluminum does not contain or emit toxic elements and as a result does not alter the smell or taste of beverages or food it contains. This is an important benefit for food preparation and storage companies. Aluminum packaging is manufactured constantly in forms that include trays, cans, containers, bottle caps, foil, and more.
The manufacturing industry takes advantage of the various unique benefits afforded by aluminum to produce highly efficient and cost-effective products. Aluminum alloys continue to be created for specific applications. The benefits aluminum offers include its strength and lightweight characteristics, low cost, corrosion-resistance, electrical and thermal conductivity, along with its most important characteristic of recyclability, making it ideal for various industries and manufacturers.