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 zinc, 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.

59 thoughts on “Super Magnesium: Lighter Than Aluminum, Cheaper Than Carbon Fiber

    1. I like the metal/wax then sintering, low temp hot end, precise can do mixes but, needs to be annealed/sintered at high temp, guess with Mg can do fine in Argon atmosphere. Saw demo just yesterday. Their carbon fibre coupling can do 10Tonne pull strength… In Perth MarkForge had wide range of printers, their full up metal printing with sintering over around AUD$175K. Well accepted so far in mining industry…

  1. Here’s a picture of a big magnesium fire at a Volkswagen casting plant in 2006: https://commons.wikimedia.org/wiki/File:Vw-baunatal-brand.jpg
    There was another much larger one in the 1960’s, that left a crater comparable to heavy bombing.
    Burning magnesium is pretty spectacular.

    Bill Shook was selling magnesium bicycle wheels for a while. They were spectacularly lightweight, but they apparently had corrosion problems. https://www.bikeradar.com/us/road/news/article/american-classic-magnesium-road-clinchers-rise-again-40274/ Likewise, the short-lived Kirk Precision frame was cast out of magnesium, and was supposed to be almost ludicrously stiff, but still had corrosion problems. https://bicycletimesmag.com/vintage-velo-kirk-precision/

    Gary Klein was making boron-fiber-reinforced aluminum bike frames in the late 1970’s. At the time, only the space program was playing with boron metal matrix composite. Throughout the late 1980’s, Specialized made hundreds of thousands of bikes with aluminum/aluminum oxide metal matrix composite, which is to this day rare stuff outside the cycling world, while to my knowledge nobody outside the military is still working with boron-reinforced aluminum.

    1. I’m surpised it was considered stiff. The Young’s modulus (stress per strain) for magnesium is lower than for aluminium, 45 GPa vs 70 GPa, whereas for steel it is 210 GPa so it takes relatively little force to bend a magnesium part out of shape.

      That’s the main problem in using these lightweight alloys. You make your part with exact dimensions, and then it goes pear shaped and warps, so you have to use considerably more material to distribute the stresses and that loses you a great deal of the weight advantage. Sometimes it negates the advantage entirely.

  2. Powdered wheat also burns spectacularly. The main feature of magnesium fires, along with other metals, is that water makes them worse. Still, igniting magnesium is a tough thing to do, and usually uses very thins strips so that the heat for ignition is not conducted away too fast. Try holding steel wool to the terminals of a fresh battery to see what iron can do if finely divided.

    1. Not as hard as you might think. When I was a kid, my Dad used to bring home magnesium printing plates from work, and we would burn them in the driveway. He had almost no trouble lighting them with his Bic cigarette lighter, he just had to hold the heat on for a while.

          1. I mean, if we’re being really pedantic, the temperature is stated as 1200F, not 1200.00F, so the significant digit is the ones column, not the hundredth column, makeing the correct notation or the conversion 649C.

    1. There is always one in the group that is mad about technicalities. Here is something for you to think about: The system of temperature (Fahrenheit ) was devised by Germans and delivered to America through the natural course of the educations systems and publications…blah, blah. So once it was here int the States everyone used it for everything and found it handy, it is familiar and just fine. Then some folks said hey why aren’t you using Celsius? And we said nah, we don’t need to base all temperatures on how water reacts to it. Also no one wants to change when the old country tells you to. It’s like you finally grew up (and you are frick’n huge) and you get away from your abusive parents, then they come over to your mansion and start telling you what color the walls should be. Forget that garbage.

      1. Meanwhile the civilized world has adopted the SI system, so we don’t have to remember that 12 inches is a foot, and if we need fractions of a meter we can just divide by a factor 10, etc, etc.

        And we can easily calculate energy, as the Kelvin/Celsius temperature fits nicely into the math, etc, etc.

        Not to speak about time and date formats – sigh…

        But ok US, maybe you will enter the 20’th century when the rest of the world enters the 22’nd.

        1. 12 inches to the foot, 3 feet to the yard, 5.5 yards to the rod, all good. The problem with non-SI historically is that the size of an inch, an ounce, a gallon, etc differed from place to place. They still do. An Englishman ordering a pint in the US feels cheated, getting only (about) 80% of what he was expecting.

          The French tossed out the inch, ounce, gallon, and all the units based on them, and replaced them with the meter, the gram, the liter, which were not related to the old units and were given universal values. An Englishman ordering a half-liter in the US will, after some stares from the barman, probably get something close to a half-liter.

          That’s the real advantage of SI: It’s the same everywhere.

          1. I hope when I’m 95, I can still come to Hackaday comments and see people post the exact same comments about how “they have to remember that 12 inches is a foot”. It’s so familiar and meme at this point it’s comforting.

        2. Wow, sounds like you have everything figured out nicely over there. It never makes sense to use a system for historical reasons, or because people are used to it. So I’m curious, how many seconds are in your minute? How many minutes in an hour? Hours in a day? Days in a week? Days in a month (hopefully constant unlike our system)? Weeks in a month? Months in a year?

          1. The babylonian origin (IIRC) of the clock numerics is (AFAIK) universal (on Earth), so no need to argue over units or errors in converting to what ?. It therefore makes sense to adopt SI units for the same sense of universality (On Earth) – then had this been thought of earlier the stuff-ups of Eg a mars lander wouldn’t have occurred… There are other examples of unit stuff ups that occur with SI vs imperial best left for a forum on risk assessment. Fortunately seconds, minutes, hours has no such problem with conversions due to its wide acceptance – as far as I know – perhaps you can offer a corollary risk assessment issue then we can well question and critique it more pointedly ?

    2. It tends to take a legacy application to keep legacy standards in use. I think most of those in the US are in home life. It wouldn’t surprise me if the fluid measurements are kept alive almost entirely by the gigantic corpus of old cook books and recipes from them. Im not so sure measuring child growth keeps feet relevant though.

    1. I sure hope it is. This isn’t the periodic table. It is the standard nomenclature for magnesium alloys. So A is aluminum which is also not correct if you are confusing it with a periodic table. But since it isn’t a periodic table, it is fine. I’m not sure where you got the idea that the nomenclature used element names off the periodic table. After all, E for “Rare Earths” was a dead give away.

      A Aluminium
      B Bismuth
      C Copper
      D Cadmium
      E Rare earths
      F Iron
      H Thorium
      J Strontium
      K Zirconium
      L Lithium
      M Manganese
      N Nickel
      P Lead
      Q Silver
      R Chromium
      S Silicon
      T Tin
      V Gadolinium
      W Yttrium
      X Calcium
      Y Antimony
      Z Zinc

      1. the article states “Z is for zirconium,” yet the list shows it is for zinc. Stupid system if you ask me (or probably any chemist). Would have been a lot more straightforward if the chemical symbols had been used

  3. “they claim are 30% lighter than aluminum, as well as stronger and stiffer than the equivalent mass of that metal”

    Meaning stronger and stiffer than kitchenware grade 1000 aluminum? yeah that’s not a great achievement on the other hand.

    My experience with magnesium (alloyed) is limited but I noticed you can cut it with whatever tool you have. Even rubbing it with a spoon or a wood splinter will do.

  4. Let us know when they make something lighter and stiffer than carbon fiber and cheaper than aluminum.

    Given that these formerly military and aerospace only alloys are being let out for the proles, there’s likely something that meets those specs, at least the lighter and stiffer than carbon fiber, probably not cheaper than aluminum.

    1. There is a beryllium cast alloy these days. Gets used in the F-35 to isolate the instruments below the nose from vibration.

      Pure beryllium has higher performance and was used for crankshafts in F1 cars before they banned it from the sport for being too expensive.

    1. If you’re already on fire you may not care that your doohickey is starting to burn as well. Conversely it might not seem important that some part of your doohickey didn’t burn while every other part of it and everything around it was reduced to ash.

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