Magnesium is naturally abundant and extremely lightweight but hasn’t been an overly popular choice for automotive structural components to date. Magnesium alloys show promise, yet until recently, suitable alloying elements for structural components of vehicles have been limited to rare and expensive ones. Matmatch discusses future developments in the magnesium extrusion process that could change the game.
The Favourable Properties of Magnesium
Of all the materials used in engineering, magnesium is the lightest. Its density measures 1.74g per cubic centimeter, much lighter than aluminum and significantly lighter than steel. It’s also widely available – the fourth most abundant element in the Earth and the third most abundant element in the oceans, to be exact. Magnesium is ductile, can be cast easily and dampens noise and energy effectively. It is dimensionally stable, has a low galling tendency and resists impact well. All these are favorable properties for structural components.
Alone, magnesium lacks the strength to be relied upon for use in structural components of vehicles, but alloying quickly solves this problem. Magnesium is most frequently alloyed with aluminum, manganese, zirconium, zinc or rare earth materials, all of which serve to increase strength and durability, facilitate precipitation hardening or improve casting potential and corrosion resistance.
Environmental and Economic Considerations
In 1975, the United States Congress introduced standards for Corporate Average Fuel Economy (CAFE), in a bid to improve fuel economy in American trucks and cars. CAFE is determined mathematically, taking a vehicle’s carbon footprint into consideration and determining a fuel economy target.
In addition to adherence to CAFE standards, consumers have revived their interest in reducing carbon dioxide emissions and preventing or delaying harmful global warming. As fuel efficiency is directly linked to CO2 emissions, weight reduction has become a key focus for automotive manufacturers.
Finally, manufacturers must consider production prices. Magnesium has not been viable as a major structural component because alloying with rare elements raises the price far beyond aluminum and plastics.
The ShAPE Approach
Researchers at the Pacific Northwest National Laboratory (PNNL) of the US Department of Energy have developed a promising new process for magnesium extrusion. The process is called Shear Assisted Processing and Extrusion (ShAPE), and is patent pending.
This method differs from traditional extrusion by combining the process with spinning to create the ideal temperature for softening the metal as it is pressed through a die. While traditional extrusion requires the use of resistance heaters that consume a lot of energy, the spinning process gets the heat just right and concentrates it at the desired location at a fraction of the energy cost. In addition to the production cost savings, researchers claim that the measure enhances the magnesium alloy’s ductility and energy absorption in the process.
The Future of Magnesium Alloys in Structural Components
Manufacturers and consumers alike are interested in solving some of the setbacks that have hindered the use of magnesium alloys in automotive structural components so far. Exciting developments such as the ShAPE approach could reduce costs, eliminate the need for rare earth materials and simplify treatment processes significantly, making magnesium alloys a worthy contender in this market.
Want to Discover More About Magnesium?
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