Pub. 7 2017 Issue 2

15 MINING FOCUS • Titanium and titanium alloys: Titanium offers as much strength as steel, resists high temperatures, and has low cor rosion when compared with steel and aluminum. Unfortunately, it is heavier than aluminum. Engineers use it in areas such as hydraulic systems, in panels, and in swivel wing assemblies. The only problem is its cost, but that hasn’t stopped engineers from using titanium when it makes sense to do so. For example, the Lockheed SR- 71 Blackbird is made out of titanium. This important plane was built for extreme speed and was released in 1966. • Compos i t e ma t e r i a l s: When engineers designed the Boeing 787, they used composites for more than half of the materials that were required. Composite materials have been designed to offer high compression resistance, high resistance to corrosion, high tensile strength, and low weight. Composite materials usually consist of some kind of base material combined with a resin that makes the composite stronger. The most common base material is fiberglass, although another choice is graphite combined with epoxy. Composite materials increase fuel efficiency and aircraft performance because they are light, which means the direct cost to operate a plane is reduced. What are the tradeoffs? They are expensive; they need immediate repair when damaged; and they do not performwell in a fire. What materials show promise for the future of building airplanes? • Magnesium is a lightweight metal that is both strong and ductile, but it wasn’t used in the past because it corrodes and is flammable. New magnesium alloys have made it possible to use magnesium safely by reducing both corrosion and flammability. • Nano adapt i ve hybr i d f abr i c (NAHF-X), which is also called fuzzy fiber, is a material that has good electrical, structural, and thermal properties. It works well when combined with resins to create continuous sheets in any size an engineer might want. Unmanned aerial vehicles use fuzzy fiber to reduce weight. Since a skin of fuzzy fiber conducts electricity, it can be part of an aircraft’s communications, power, and sensor systems. • Fiber metal laminates have low density, high elasticity modulus, and high strength. They are tough, resist corrosion and fire, and have good fatigue properties. • CentrAL reinforced aluminum has a tensile strength that is 25 percent more than that of a high- strength aluminum alloy. It also offers high fatigue resistance and high tolerance to damage and is lighter than aluminum alloy, which translates to a lighter plane and lower fuel consumption. • Ceramic matric composites resist high temperatures, making them a good choice for engines. Use of ceramic matrix composites has decreased fuel consumption by 16 percent. It matters what materials are used to build airplanes. Too much stress will cause an airplane to buckle. Sometimes the entire structure will be destroyed. Although engineers design aircraft to resist buckling, sometimes they also deliberately design slight buckling into small areas and small parts. Buckling is something that is affected by the choice of physical properties and by the shape and thickness of a particular structural material. So next time you safely fly to your favorite vacation destination or take a business flight, think about the hard working miner that made it all possible. Because without mining, air travel as we know it today would not exist. It’s yet another example of how mining make your life possible. X Airships, in fact, looked like the direction of the future for air travel . It wasn’t until the Hindenburg aircraft caught fire and crashed in 1937 at Lakehurst, New Jersey, killing the 36 people who were on board at the time, that the idea of airships built to carry passengers came to an end.