Super Magnesium: Lighter Than Aluminum, Cheaper Than Carbon Fiber
We think of high tech materials as the purview of the space program, or of high-performance aircraft. But there are other niche applications that foster super materials, for example the world of cycling. Magnesium is one such material as it is strong and light, but it has the annoying property of burning in its pure state. Alloys of magnesium meanwhile generally don’t combust unless they are ground fine or exposed to high temperatures. Allite is introducing a new line known as “super magnesium” which is in reality three distinct alloys that they claim are 30% lighter than aluminum, as well as stronger and stiffer than the equivalent mass of that metal. They also claim the material will melt at 1200F instead of burning. To lend an air of mystique, this material was once only available for defense applications but now is open to everyone.
It’s a material that comes in three grades. AE81 is optimized for welding, ZE62 is better suited for forging, while WE54 is made for casting processes. Those names might sound like made up stock numbers, but they aren’t, as magnesium allows typically have names that indicate the material used to mix with the magnesium. A stands for aluminum, Z is for zirconium, W is for yttrium, and E stands for rare earths. So AE81 is a mix of magnesium, aluminum, and some rare earth material. The numbers indicate the approximate amount of each addition, so AE81 is 8% aluminum and 1% rare earth.
Previously, flame retardant magnesium had calcium added to the mix which raised the burn temperature significantly. There remains a widespread perception that magnesium alloys easily burn, but that’s because elemental magnesium burns spectacularly. Typical alloys can burn, but fortunately for us that doesn’t happen at temperatures under 800F with these alloys in a solid piece of metal although powders or ribbons may burn more easily. According to the company, normal machining works well and requires less power than machining with other metals.
IF you want to see a big magnesium alloy forge, check out the Mesta. If you want to make your own wheels, maybe you should stick to aluminum for now.
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