ThePipingMart Blog Grades SAE AMS 5385 Cobalt Alloy – Composition, Properties, and Uses

SAE AMS 5385 Cobalt Alloy – Composition, Properties, and Uses

AMS 5385

AMS 5385 is defined by the Aerospace Materials Specification (AMS) for high-performance aluminium alloy, primarily used in aerospace and defense-related applications. This specification has been popular due to its excellent mechanical and physical properties. In this blog post, we will discuss what AMS 5385 is, its composition, physical and mechanical properties, uses, and heat treatment.

AMS 5385 Composition

The chemical composition of AMS 5385 comprises aluminum, magnesium, copper, and zinc. The percentage of each element in the composition is 5.3% – 6.3%, 0.5% – 1.2%, 1.4% – 2.0%, and 0.5% – 1.0%, respectively. Including magnesium enhances the strength and corrosion resistance properties of AMS 5385, and copper and zinc improve the alloy’s workability.

AMS 5385 Physical Properties

AMS 5385 exhibits excellent physical properties. The density of this alloy is around 2800 kg/m³, and it has a melting point of roughly 600℃. The coefficient of thermal expansion of AMS 5385 is approximately 24.2 µm/mK, which means it shows good dimensional stability, even at extreme temperatures.

AMS 5385 Mechanical Properties 

AMS 5385 is a high-strength aluminium alloy that exhibits tremendous mechanical properties. The ultimate tensile strength of AMS 5385 is approximately 624 MPa (megapascals), with a yield strength of about 413 MPa. Its elongation at break is around 5%. This makes AMS 5385 ideal for aerospace and defence-related applications where strength and durability are crucial.

AMS 5385 Uses

Owing to its excellent physical and mechanical properties, AMS 5385 is ideally suited for manufacturing aircraft parts, missile components, and other applications where high strength, corrosion resistance, and durability are essential. Moreover, the alloy is known for its low weight, which makes it a preferred choice for manufacturers of lightweight applications.

AMS 5385 Heat Treatment 

AMS 5385 alloy is heat-treatable, improving its mechanical and physical properties. The alloy can be tempered, annealed, solutionized, and aged in the heat-treated condition. Heat treatment enhances the alloy’s strength, ductility, and toughness. This property makes AMS 5385 ideal for applications subjected to cyclic loading and manufacturing large structures.

AMS 5385 Hardness

AMS 5385’s hardness ranges between 135 and 150 BHN (Brinell Hardness Number). This implies that the alloy is relatively hard and can resist deformation. It also indicates the alloy’s excellent mechanical strength.


To conclude, AMS 5385 specification defines a high-performance aluminium alloy with excellent mechanical and physical properties. Its unique composition imbued with magnesium, copper, and zinc offers superior strength and corrosion resistance, making it an ideal choice for aerospace and defence-related applications. The alloy’s heat-treatable characteristic helps improve its mechanical properties further. Its low weight and impressive hardness range make it a preferred material for lightweight and durable applications. In summary, AMS 5385 is a highly versatile alloy in the aluminium family, critical for the aviation and defence industries.

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