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What Are the Different Types of Metal Alloys That Exist Today?

Did you know that there are 118 known elements to date? Of these, 94 are naturally occurring. Moreover, most of them are metals, although others are non-metal.

Metals, however, account for about three-quarters of all known elements. You’re likely familiar with some of these, such as aluminum, copper, gold, iron, and platinum. These are among the most abundant metals in the earth’s crust or the ores found in it.

As impressive as those metals are, they may not be as useful or durable in pure form. As such, they undergo processes transforming them into different types of metal alloys.

Metal alloys, in turn, are metals mixed with other substances. As such, they can be lighter, harder, or stronger than pure metals.

Today, there are dozens of different types of alloys with many uses and applications. We’ll go over some of the most common ones in this guide, so be sure to read on!

Aluminum Alloys

Aluminum accounts for 8.1% of the Earth’s crust, making it the third most abundant element on the planet. It possesses favorable properties like low density, non-toxicity, and corrosion resistance. It’s also very malleable and ductile, making them excellent for sheeting and wiring.

What’s more, aluminum is very light; one cubic foot of this metal only weighs about 170 pounds. That’s about a third of the total weight of one cubic foot of steel, which is around 490 pounds.

The problem with pure aluminum is that it’s soft and weak. That’s why it needs other metals, such as copper, magnesium, and manganese. This particular mix creates duralumin, an alloy strong enough for use in airplanes.

There are many other aluminum alloys, categorized by four-digit series from 1 to 7.

For example, alloys in the 1XXX series consist of aluminum with a purity of 99% or higher. That high purity allows them to remain malleable, so you’ll find them in food packaging trays. Moreover, these alloys are ductile, which is why they go into making power lines and wires.

By contrast, aluminum alloys in the 7XXX series get mixed with zinc, and in some cases, magnesium. They’re heat-treatable and strong, making them suitable for aircraft applications.

Stainless Steel

Iron, a strong and sturdy natural element, makes up the bulk of stainless steel. However, pure iron is quite brittle, and damp or humid air can cause it to rust.

Adding chromium (Cr) to iron addresses those problems. Cr, another naturally occurring metal, is hard, heat-resistant, and corrosion-resistant. Stainless steel products contain at least 11% chromium.

So, it’s thanks to chromium that stainless steel alloys don’t burn right away when exposed to heat. These metal alloys don’t rust or stain, either, thanks to their Cr content.

Other elements, such as aluminum, copper, and nickel, make up stainless steel, too. Their additions further reinforce the strength and durability of stainless steel alloys.

What’s more, cleaning brushed stainless steel is a breeze; you only need to wipe it with some dish soap and water. This, plus its other favorable properties, make it a top material for appliances. That’s why high-end kitchen appliances, from refrigerators to ovens, are often stainless steel.

Gold Alloys

Every year, miners worldwide add 2,500 to 3,000 tons of pure gold to the existing above-ground gold stock. Jewelry, in turn, accounts for close to half of the total above-ground stocks of gold.

What not many are aware of is that most pieces of gold jewelry aren’t pure gold. That’s because 24-karat gold (the jewelry term for pure gold) is very soft, easy to wear, and prone to denting.

As such, jewelry makers mix pure gold with other elements, such as silver, copper, or titanium. This helps strengthen gold and make it harder and more durable.

Brass

Brass, a metal alloy of copper and zinc, has a history dating back to Neolithic times. Known as calamine brass, it’s the earliest known type of brass. It has since then stood the test of time, thanks to its impressive hardness and workability.

The primary types of malleable brasses are alpha brasses and beta brasses. The alpha group is a key player in manufacturing ammunition cases, bolts, pins, and screws. By contrast, beta brasses are popular materials for plumbing, door, and window fixtures.

Bronze

Copper is the main metal in bronze, followed by tin and other elements such as aluminum or manganese. Some metallurgists also add phosphorus and silicon to the mix.

Granted, steel and stainless steel replaced many of the applications of bronze. However, bronze is still an important alloy in making ship propellers. Many equipment parts, such as bearings, bushings, clips, and springs, also use bronze.

Biocompatible Alloys

Biocompatible is a medical term that refers to a material that doesn’t harm living tissue. In most cases, it pertains to dental and medical implants.

Biocompatible alloys, therefore, are safe to use and surgically implant into the body. They are also strong, corrosion-resistant, and non-toxic.

Most biocompatible alloys are surgical-grade stainless steel, cobalt-chromium, and titanium alloys. You’ll find these in many medical implants, such as screws, plates, and prostheses. As for dental implants, which replace lost tooth roots, titanium is the most common alloy used.

Amalgam Fillings

Speaking of teeth, did you know that some of the earliest tooth fillings were alloys? These are the amalgam fillings, half of the weight of which consist of elemental mercury. A powdered alloy mix of copper, silver, and tin makes up the rest of the dental fillings.

Amalgam fillings are so common that 100 million people in the US have them in their teeth. Although controversial due to their mercury content, experts confirm that they are safe.

Take Your Pick among These Types of Metal Alloys

There you have it, your ultimate guide on the many different types of metal alloys and their uses. Now that you know their properties, you can choose the most suitable alloys for your project. Just remember that the more abundant the alloy is, the more cost-effective it usually is, too.

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