ThePipingMart Blog Grades AMS 4166 Aluminium Alloy – Composition, Properties and Uses

AMS 4166 Aluminium Alloy – Composition, Properties and Uses

AMS 4166

The aerospace industry is one of the most advanced industries requiring high-performance metals to manufacture aircraft components. Various metals are used in aerospace engineering, each with specific properties essential for aerospace applications. AMS 4166 is a significant grade of aluminium alloy widely used in manufacturing aircraft components. This blog will discuss what AMS4166 is, its composition, physical and mechanical properties, uses, and much more.

What is AMS 4166?

AMS 4166 (also known as Aluminium 7075) is a high-strength aluminium alloy that belongs to the 2000 series of aluminium alloys. It is a heat-treatable alloy with excellent mechanical properties like high strength, toughness, and fatigue resistance, making it suitable for aircraft applications. AMS4166 has good corrosion resistance, making it ideal for aerospace applications.

What form is AMS 4166 Available at Piping Mart?

  • Pipes
  • Tubing

AMS 4166 Composition

AMS 4166 comprises copper, magnesium, and silicon, the main alloying elements. These alloying elements give AMS 4166 unique properties, including high strength, toughness, and machinability. Other features present in the composition include iron, manganese, and zinc, which contribute to the alloy’s overall properties.

Component Elements Properties Metric English Comments
Aluminum, Al 87.1 – 91.4 % 87.1 – 91.4 % As remainder
Chromium, Cr 0.18 – 0.28 % 0.18 – 0.28 %
Copper, Cu 1.2 – 2.0 % 1.2 – 2.0 %
Iron, Fe <= 0.50 % <= 0.50 %
Magnesium, Mg 2.1 – 2.9 % 2.1 – 2.9 %
Manganese, Mn <= 0.30 % <= 0.30 %
Other, each <= 0.05 % <= 0.05 %
Other, total <= 0.15 % <= 0.15 %
Silicon, Si <= 0.40 % <= 0.40 %
Titanium, Ti <= 0.20 % <= 0.20 %
Zinc, Zn 5.1 – 6.1 % 5.1 – 6.1 %

AMS 4166 Physical Properties

AMS 4166 has a density of 2.78 g/cc and a melting point of 565°C. It also has a thermal conductivity of 123.5 W/m.K, which is relatively high, making it suitable for temperature-sensitive applications. A moderate coefficient of thermal expansion is also seen, which helps prevent stress in the alloy during thermal cycling.

Physical Properties Metric English Comments
Density 2.81 g/cc 0.102 lb/in³ AA; Typical

AMS 4166 Mechanical Properties

AMS 4166 has excellent mechanical properties, such as high-strength and stiffness, which make it ideal for aerospace applications. Its tensile strength ranges from 490-600 MPa, while its yield strength is around 350-400 MPa. The alloy also exhibits good elongation, around 15-20%. The fatigue strength of AMS 4166 is 123 MPa, making it suitable for use in aircraft parts that undergo constant cyclic loading.

AMS 4166 Uses

AMS 4166 produces aircraft components like wing spars, bulkheads, and fuselage frames. It is also widely used in military aircraft applications. The alloy’s high strength, toughness, and fatigue resistance make it suitable for applications where performance and reliability are critical.

AMS 4166 Hardness

AMS 4166 has an average hardness of 125 Brinell. The alloy’s hardness can be enhanced through heat treatment, which increases its strength and stiffness. The hardness and power are closely related because the more complex the material, the higher the strength.

AMS 4166 Heat Treatment

AMS 4166 is a heat-treatable alloy, and the heat-treatment process involves a series of heating and cooling cycles to modify the alloy’s properties. The heat treatment process for AMS 4166 is T6 tempering, which consists in quenching the alloy at a high temperature, followed by ageing at a lower temperature for several hours. This process improves the alloy’s strength, making it suitable for aerospace applications.


In conclusion, AMS 4166 material is a high-performance aluminium alloy widely used in aerospace. It has unique properties such as high strength, toughness, and good fatigue resistance, making it ideal for aircraft component applications. Understanding its composition, physical and mechanical properties, uses, hardness and heat treatment process is crucial when deciding its use. AMS 4166 offers excellent value for money and unparalleled reliability in the aerospace industry.

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