Types of Alloys and Their Uses

We come across various alloy types during our day-to-day lives. They are all around us; in the utensils we use, decorative items around the house, etc.
Metallic materials comprising a combination of more than one metal and some other element or metal are termed as alloys.

When two or more metals or non-metals are combined together and intimately mixed by fusion, electrolytic deposition, etc. the final product or alloy formed is stronger and more durable for practical use, as compared to the base metal. The different metals that are used to prepare alloys are zinc, copper, tin, aluminum, chromium, nickel, silver, etc. Moreover, the different non-metallic elements used to make alloys are carbon, boron, sulfur, zinc, etc. Depending on the composition of metal or non-metal in the alloy, we have different types of alloys being formed.

There are scores of different types of alloys that are prepared from a combination of metals and non-metals. There can be different types of alloy metals, such as binary alloys, which are created by combining two materials, either two metals or one metal and one non-metal or ternary alloys, that are created by combination of three elements. For an alloy to be formed, the presence of at least one metal is essential. In this article we will only look at some common types and their uses.

Stainless Steel Alloy and its Uses


Composition

This name stainless steel is commonly referred to those metal alloys comprising 10.5% or more Chromium (Cr) and 50% Iron (Fe) in it. The chromium present in it gives stainless steel its highly corrosion resistant property. Pure iron is unstable and corrodes naturally by rust formation. By the addition of chromium, iron is prevented from combining with oxygen and water to form rust. This highly stain resistant alloy looks bright because of its ability to reflect light. There are different types of stainless steel depending on the amount of chromium, iron and other metals in them.

Type of Stainless SteelComposition
MartensiticIron, 12-14% Chromium, 0.1-1% Carbon, 0.2-1% Molybdenum
FerriticIron, 11-18% (17%) Chromium, 0.08-0.2% Carbon
AusteniticIron, 17 - 25% Chromium, 10-20% Nickel, 0.15-2% Carbon
DuplexIron, 19-28% Chromium, less than 5% Molybdenum, 1-6% Nickel

Where is it used?

It is used to make kitchen utensils, as stainless steel forms one of the most hygienic surfaces to store and prepare food in. Neither do they affect the flavor of the food, nor do they react with acidic foods during cooking. Moreover, since it has no pores in its surface it does not collect germs, dirt or grim, thereby making it very easy to clean. Besides cookware, stainless steel is also used for preparing surgical instruments, reinforcement bars, masonry support, washing machine drums, ships, chemical tankers, etc.

Brass Alloy and its Uses


Composition

Formed by a combination of zinc and copper, brass is a light yellowish to dark, reddish-brown color alloy. The color range will deviate according to the amount of zinc present in brass. The higher the zinc content, the lighter will be the color. Again brass can be divided into several types depending on its composition. Here are a few of them.

Types of Brass AlloyComposition
Admiralty BrassCopper, 28% Zinc, 1% Tin
Red BrassCopper, 5% Tin, 5% Lead, and 5% Zinc
Yellow BrassCopper, 33% Zinc
White BrassCopper, >50% Zinc
Aluminum Brass76% Copper, 22% Zinc, 2% Aluminum
Nickel Brass70% Copper, 24.5% Zinc and 5.5% Nickel
Lead-free BrassCopper, Zinc and less than 0.25% Lead
Manganese Brass70% Copper, 29% Zinc, and 1.3% Manganese

Where is it used?

Brass is malleable, a good conductor of heat, resistant to salt water corrosion, etc. which is why it used to make items that come in contact with harsh environment such as tubes, pipes, weather stripping and several architectural trim pieces. Brass' excellent acoustic properties make it suitable for wind musical instruments. Instruments like euphonium, trombones, saxophone, tubas, horns, etc. are made from brass. Moreover, since brass does not tarnish easily, it is also used to make utensils, cutlery and other small decorative items. Its thermal conducting property makes it useful in the manufacture of radiators and heat exchangers such as oil coolers, air conditioners and heater cores.

Sterling Silver Alloy and its Uses


Composition

Silver in its purest form is malleable, ductile and extremely soft. This extreme softness makes it easy to work with, however, it also has its drawbacks. This causes silver to be scratched and deformed easily, thereby making it not suitable for manufacture of functional items. Thus, pure silver (92.5%) is combined with 7.5% copper metal to get 925 sterling silver. The copper metal gives silver, the ample strength required. Besides copper, even germanium, platinum and zinc can be added to the silver to form sterling silver.

Where is it used?

Sterling silver is used to make 925 silver jewelry. Another popular use of sterling silver is for the manufacture of tableware. Silver knives, spoons, forks, trays and tea sets are made and used by the elite. Since sterling silver is naturally aseptic and is also resistant to antiseptics, heat sterilization and body fluids, it is used in the manufacture of medical instruments. Moreover, it is also used to make musical instruments like flute and saxophones.

These were just three types of alloys and their uses. Alloys are truly beneficial because metals in their pure form are mostly very delicate to be used to make functional items. However, by alloy formation, we have been able to put all these metals to good use.