What are common materials used in aerospace machined parts?

In selecting materials for aerospace parts, one of the major considerations is the strength-to-weight ratio. Fatigue resistance, and ability to perform under extreme temperatures and stress are also major material considerations. The most common material categories include:

Aluminum alloys – These alloys are widely used for structural components, brackets, and housings. They are light weight and have good machining characteristics. The most popular grades include 6061-T6 (most common), 7075-T6 (high strength), and 2024 (fatigue resistance).

Stainless steels – Often used in landing gears, fasteners and fittings. Common stainless grades are 15-5PH and 17-4PH. They offer high strength and corrosion resistance.

Steel alloys – High-strength steels (e.g., 4340) are used for landing gear and other heavy-load components.

Titanium alloys – Used in engine components (high stress, high heat) landing gear, and fasteners. Ti-6Al-4V is the most common grade. It is valued for strength, corrosion resistance and heat tolerance. It’s more difficult to machine than aluminum.

Nickel-based superalloys – Turbine engines and exhaust systems are made up of materials like Inconel 718 and Inconel 625 are used in turbine engines, and exhaust systems. They have exceptional strength and can withstand high temperatures.

Composites – Are becoming more popular. The machining of composites is considerably different than metal components, but because of their desirable structural strength/light weight ratio. They are increasingly used alongside machined metal parts.

Materials are application specific. The selection is based on the part’s specific load, thermal, and weight requirements.