Aluminum once made up most of the material used in aerospace applications. However, aluminum makes up only 20 percent of the material used in a typical jet today. Due to the demand for light aircraft, composites, carbon-reinforced polymers and honeycombs are increasingly used in the aerospace industry.
Other requirements — such as the ability to withstand high temperatures and pressures and resistance to corrosion — differentiate other materials that were previously considered impossible for the aerospace industry.
Although the use of aluminum in many aspects of aerospace production has declined, aluminum is still widely used in modern aircraft. Aluminum remains the strongest and lightest material for many specific uses. Due to its high ductility, it can be easily machined and is relatively inexpensive compared to many composite materials or titanium. It can also be further strengthened by alloying it with other metals such as copper, magnesium, manganese and zinc, or by cold or heat treating it.
When exposed to air, aluminum’s tight chemical oxide bonds mean it is isolated from the environment, making it highly resistant to corrosion. Aluminum can also be processed in a number of ways to suit an equally broad range of uses, and its high electrical conductivity makes it an ideal raw material for many applications.
The most popular aluminum alloys used to make aerospace parts include:
Aluminum alloy 7075 (aluminum/zinc)
Aluminum alloy 7475-02 (aluminum/zinc/magnesium/silicon/chromium)
Aluminum alloy 6061 (aluminum/magnesium/silicon)
Which alloy to choose depends entirely on the purpose of the end. Many aluminum parts on aircraft are purely cosmetic, while others are highly functional and require specific characteristics.
Stainless Steel Parts for Aerospace Applications
Stainless steel is an alloy made from an alloy of steel and chromium. The strength of stainless steel is directly related to the chromium content in the alloy. The higher the chromium content, the higher the strength of the steel.
While stainless steel is stronger than aluminum, it is also generally quite heavy, preventing its widespread use in aerospace applications. However, stainless steel components have two main advantages over aluminum:
Stainless steel has strong corrosion resistance.
Stainless steel is stronger and more resistant to wear. Stainless steel parts can handle scratch/impact damage better than aluminum parts.
Stainless steel alloys are increasingly used in aircraft components that require high strength but can withstand increased weight. The high corrosion and temperature resistance of stainless steel makes it suitable for a range of aerospace components including actuators, fasteners and landing gear components.
Learn more from aerospace machining experts
Aluminum has been widely used in the aerospace industry in the past, but in recent years the aerospace industry has broadened its horizons and has come to rely on a wider range of materials. However, the advantages of aluminum alloys still make aluminum a major resource in the aerospace field.
Despite the heavier weight, the use of stainless steel has recently increased in aerospace applications, especially for parts that require high strength, corrosion resistance and temperature resistance.