Aluminum is the most common non-ferrous metal on the planet. It’s extremely likely that you interact with aluminum on a daily basis.
In fact, the use of aluminum has totally changed how the world works.
In this article, I’ll explain why aluminum is so common and what it’s used for.
Why Aluminum is So Common
Using aluminum has some really distinct advantages, which kinda explains why we see it all over.
For one, it’s highly recyclable. This means that it’s not nearly as bad for the environment compared to some other materials. It’s actually one of the most sustainable metals out there.
It’s also very easy to bend, form and cut. That means it’s a great material to work with.
It’s lightweight and strong. Pound for pound, it’s actually stronger than steel. It’s around 1/3rd the weight of steel, but it can carry 2/3rds of the same load that structural steel carries. So 1 pound of aluminum carries more than 1 pound of steel, but a 1 inch thick bar of steel carries more than a 1 inch thick bar of aluminum.
It’s corrosion resistant. Regular steel will rust and rot away when put in contact with water. Aluminum doesn’t react to water. It does, however, corrode when in contact with salt. That means that aluminum doesn’t do well around seawater or salty roads, but otherwise it holds up very well over time.
Aluminum is also a great electrical conductor. While it doesn’t conduct electricity as well as copper, the combination of being lightweight and conductive give it a few really distinct advantages. More on that later.
Airplanes use a massive amount of aluminum. Its strength-to-weight ratio, low cost, and high manufacturability mean that aluminum aircraft can be (relatively) easy to make and cheap to run. The fuel savings from lighter aircraft also means less of an impact on the environment.
Even spacecraft made from anywhere from 50 to 90% aluminum because of these advantages.
Actually, at one aerospace manufacturing facility I worked at, we’d process about 30 tons of aluminum every year making aircraft structural components. We’d turn about 80% of that into chips and send it back for recycling.
Beyond aircraft, some high speed trains are made of a high percentage of aluminum to keep them lightweight and low maintenance. Car engine blocks are also much lighter and easier on fuel compared to back when they were made from iron.
Aluminum is a common material used in high-end electronics, particularly in casings for laptops, phones, and tablets. It doesn’t crack like plastic, so it’s more durable, and it looks really sleek. It’s also not an insulator, so it can help prevent overheating of electronics.
For example, Apple uses lots of aluminum for their iPhones and Macbooks. You’ll also see them in other products like headphones and other sound equipment.
Another common household application of aluminum is in cookware. It does a great job of transferring heat, so you’ll see it in pots, pans, etc. Aluminum foil is another common one. Guess what it’s made of?
Aluminum cans are the gold standard for carbonated beverages. Aluminum is strong enough to be papery thin and withstand pressure and impact, it doesn’t corrode, it’s environmentally friendly, and it’s safe.
In the 60’s and mid 70’s aluminum wiring was used as a cheap alternative for homes, but it was fazed out afterwards because of fire hazard concerns.
Actually, there’s nothing wrong with aluminum wiring itself, at it can be used safely in the home. There are just some special considerations that come into play when aluminum wires are used.
For one, aluminum doesn’t conduct electricity as well as copper does. This means that the aluminum wire needs to be thicker that it would be if it was made of copper.
Another is that aluminum is softer and easier to damage. Electricians need to be more careful not to nick or damage aluminum wires so make sure that there aren’t any spots that can constrict the flow of electricity and get hot.
Aluminum expands and contracts more than copper does due to temperature. That means that we need to use an appropriate connector that won’t loosen as the wires warm up.
The last main difference between copper and aluminum wires is oxidation. Copper oxide will still conduct electricity, aluminum oxide won’t. Again, this means that the connections need to be able to prevent oxide from building up, blocking electrical flow, and getting hot.
Today, most people (and insurance companies) simply choose to avoid aluminum wiring. When it is used, though, it just means that there will be a bit more the inspector needs to pay attention to to make sure that it’s safe.
For high voltage lines, though, aluminum is actually preferred. Aluminum has a better conductivity to weight ratio than copper, so it’s the metal of choice for power grids and overhead power lines. Lightweight, strong aluminum makes it possible to have a greater distance between posts, since the cables don’t weigh as much.
The formability of aluminum makes it a really appealing choice for modern architecture; we can make interesting shapes and bends that are otherwise very difficult to do.
Because of its recyclability and availability, aluminum is considered a highly energy efficient and sustainable construction material. It’s also very low maintenance.
The first large building to really make use of a significant amount of aluminum is the Empire State Building in New York. Built in 1931, it used aluminum on lots of the decorative elements, like entrances, doors, and trim.
Now it’s a popular choice for cladding and framework for things like glass structures in construction. When anodized, it doesn’t need to be painted or coated, so it’s extremely fast to put together.
The modern skyscraper couldn’t be built without aluminum. Aluminum structures weigh 35 to 65 percent less than steel ones and are equivalent in strength.
Interesting Facts About Aluminum
Aluminum comes from a mineral called bauxite. For every 4 pounds of bauxite, we can get 2 pounds of alumina. From every 2 pounds of alumina, we can get 1 pound of aluminum.
In the 1800’s, aluminum was worth significantly more than gold. That’s because it was so difficult to make; it requires massive amounts of electricity. Developments like electrolysis and 3-phase electricity have helped it to become highly accessible.
Aluminum makes up about 8% of the Earth’s crust by weight. It’s the third most common element on the planet.
It melts at 1,200 degrees Fahrenheit. Steel melts at around 2,500 degrees Fahrenheit. This is a large part of why aluminum is so recyclable; it takes a fraction of the energy to melt it back down.
Interested in learning about a few other metals? Then check out this article about different metals and their uses.