ThePipingMart Blog Grades AMS 4189 Aluminum Alloy – Composition, Properties and Uses

AMS 4189 Aluminum Alloy – Composition, Properties and Uses

AMS 4189

AMS 4189 is a popular alloy widely used in the aerospace industry. It is a high-strength alloy with excellent machinability and good corrosion resistance. This blog post will examine this alloy and discuss its composition, physical and mechanical properties, applications, hardness, and heat treatment. Whether you are a professional in the aerospace industry or just someone curious about materials science, this guide will provide a comprehensive overview of AMS 4189.

What is AMS 4189?

AMS 4189 (also known as Aluminum Alloy 4643) is a military specification that outlines the requirements for a particular type of wire used in aircraft electrical systems. While it may sound like a very niche topic, the importance of this specification cannot be overstated. Aircraft safety relies heavily on the intricate electrical systems that run throughout the aircraft, and any failure of these systems could have catastrophic consequences. That’s where AMS 4189 comes in – by providing the detailed specifications for this particular wire, the military ensures that the aircraft running these electrical systems are as safe and reliable as possible. So, while it may not be the most glamorous topic, understanding AMS 4189 is crucial for anyone involved in designing or maintaining aircraft electrical systems.

AMS 4189 Composition

AMS 4189 is a copper alloy containing a high percentage of copper (Cu) and nickel (Ni). Its chemical composition is as follows: Cu 85.0%, Ni 11.0%, Fe 2.5%, Si 0.75%, Mn 0.60%, Al 0.50%, and Zn 0.25%. The alloy also has small amounts of other elements, such as phosphorus, lead, and sulfur. The precise composition of AMS 4189 is critical to its performance, and it is essential to ensure that the alloy is produced to specific standards.

AMS 4189 Physical Properties

AMS 4189 is a non-magnetic, corrosion-resistant alloy with good thermal and electrical conductivity. Its density is 8.94 g/cm3, with a melting point of 1097°C (2010°F). The alloy’s coefficient of thermal expansion is relatively low compared to other alloys, meaning that it is less likely to warp or deform at high temperatures. AMS 4189 is also highly oxid-resistant, making it an ideal material for harsh environments.

AMS 4189 Mechanical Properties

AMS 4189 has high tensile strength and excellent fatigue resistance, making it ideal for critical aerospace applications. Its yield strength is 775 MPa (112,000 psi), and its ultimate tensile strength is 965 MPa (140,000 psi). The elongation at break is 10%. The alloy can withstand high temperatures and maintains its mechanical properties even at elevated temperatures. It is resistant to stress corrosion cracking and has excellent machinability.

AMS 4189 Uses

AMS 4189 is used in various applications, primarily in the aerospace industry. Its high strength, good machinability, and corrosion resistance make it an ideal material for aerospace components such as gears, shafts, and valve components. The alloy is also used in marine and chemical processing equipment where its corrosion resistance is crucial. AMS 4189 is often used in combination with other materials in complex structures.

AMS 4189 Hardness

The hardness of AMS 4189 depends on its heat treatment. The annealed state of the alloy has a Brinell hardness of approximately 140 HB. Heat-treating the alloy can increase its strength and hardness. The maximum hardness that can be achieved is typically around 26 HRC (Rockwell C hardness). The heat treatment process must be carefully controlled to ensure the alloy’s properties are not adversely affected.

AMS 4189 Heat Treatment

AMS 4189 can be heat-treated to increase its strength and hardness. The most common heat treatment process is solution annealing, followed by precipitation hardening. This process involves heating the alloy to a high temperature to dissolve precipitates, followed by rapid cooling to form a supersaturated solid solution. The solution is then aged at a lower temperature to allow the precipitates to grow, strengthening the alloy.


AMS 4189 is a popular alloy used in the aerospace industry due to its high strength, excellent machinability, and corrosion resistance. Its composition, physical and mechanical properties, uses, hardness, and heat treatment are critical factors determining its performance in real-world applications. By understanding the unique properties of AMS 4189, engineers and designers can make informed decisions when selecting materials for demanding applications.

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AMS 4189 Aluminum Alloy – Composition, Properties and Uses

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