ThePipingMart Blog Grades AMS 4091 Aluminium Alloy – Composition, Properties and Uses.

AMS 4091 Aluminium Alloy – Composition, Properties and Uses.

AMS 4091

Regarding materials science, AMS 4091 is a significant player in engineering, especially aerospace applications. This aluminium alloy has a unique composition, physical and mechanical properties, heat treatment and hardness, which make it an ideal choice for numerous applications. In this blog, we will explore what AMS4091 is, its composition, physical and mechanical properties, uses, and how it is heat-treated to achieve maximum performance.

What is AMS 4091?

AMS 4091 ( also known as Aluminium 6061 Alloy) is a specification of an aluminium alloy introduced by SAE International (Society of Automotive Engineers). This grade of aluminium is known for its high strength and toughness, making it ideal for use in the aerospace industry for structural components and other critical applications. Manufacturers use AMS4091 to produce parts that require exceptional resistance to fatigue and crack propagation, essential in ensuring the safety of passengers and crew members in aircraft. The specifications outlined in AMS 4091 make it one of the most reliable and widely used materials in the aerospace industry.

What Form Is AMS 4039 Available at Piping Mart?

  • Pipes
  • Tubing
  • Sheet Plates
  • Pipe Fittings
  • Forged Fittings

AMS 4091 Composition

AMS 4091 is an aluminium alloy with various materials, including magnesium, silicon, and a small amount of copper. Its chemical composition includes approximately 0.5% magnesium, 0.15% copper, 0.5% silicon, and 0.5% iron. Aluminium accounts for the remaining 98% of the alloy. The chemical composition of AMS 4091 is designed to enhance its overall properties, including strength, resistance to wear, and corrosion.

Element Content (%)
Aluminium / Aluminum, Al 97.9
Magnesium, Mg 1
Silicon, Si 0.60
Copper, Cu 0.28
Chromium, Cr 0.20

AMS 4091 Physical Properties

AMS 4091 features excellent physical properties that make it ideal for various applications. This aluminium alloy has a melting point of 488°C, a density of 2.75g/cm³, and a thermal conductivity of 146W/mK. Its thermal expansion coefficient is also relatively low at 23.2-23.7×10-6/K. These physical properties make AMS 4091 an exemplary material for aerospace applications requiring high heat, stress, and wear resistance.

Properties Metric Imperial
Density 2.7 g/cm3 0.0975 lb/in3
Melting point 588°C 1090°F

AMS 4091 Mechanical Properties

AMS 4091 is known for its high strength and hardness. It has a tensile strength ranging from 517-620 MPa and yield strength of 414-510 MPa. Additionally, it has a Brinell hardness score measured at 150 after heat treatment. This unique combination of mechanical properties and its lightweight make AMS 4091 ideal for aerospace uses such as manufacturing fasteners, brackets, and other machinery components.

Properties Metric Imperial
Tensile strength 310 MPa 45000 psi
Yield strength 276 MPa 40000 psi
Shear strength 207 MPa 30000 psi
Fatigue strength 96.5 MPa 14000 psi
Elastic modulus 68.9 GPa 10000 ksi
Poisson’s ratio 0.33 0.33
Elongation 12-17% 12-17%
Hardness, Brinell 95 95

AMS 4091 Equivalent

AMS 4117 ASTM B247 ASTM B429 DIN 3.3211 MIL G-18014 QQ A-200/8
ASTM B209 ASTM B307 ASTM B483 MIL A-12545 MIL G-18015 QQ A-225/8
ASTM B210 ASTM B313 ASTM B547 MIL A-22771 MIL P-25995 QQ A-250/11
ASTM B211 ASTM B316 ASTM B548 MIL F-17132A MIL T-7081 QQ A-367
ASTM B221 ASTM B345 ASTM B632 MIL F-18280 MIL W-23351 QQ A-430
ASTM B234 ASTM B361 ASTM F467 MIL F-39000 MIL W-85 QQ WW-T-700/6
ASTM B241 ASTM B404 ASTM F468 MIL F-3922 QQ A-200/16 SAE J454

AMS 4091 Uses

AMS 4091 is commonly used in the aerospace industry for various purposes, including manufacturing airframe components, fasteners, and structural parts. It is popular due to its lightweight, strength, and durability, all essential in aerospace applications. This aluminium alloy is also used in other industries, such as automotive, marine, and construction, where its lightness and excellent properties are desirable.

AMS 4091 Heat treatment

AMS 4091 is heat-treated to improve its mechanical and physical properties. Heat treatment involves heating the aluminium alloy material for a specific duration at a certain temperature and then cooling it through quenching. The process affects the structure and composition of the alloy, resulting in improved strength, hardness, and wear resistance. It also provides better machinability and weldability.


AMS 4091 is a crucial material in modern engineering widely used in the aerospace and automotive industries. It boasts excellent physical and mechanical properties, including high hardness, strength, resistance to corrosion and wear, and lightweight. The use of AMS 4091 in aerospace applications ensures that modern aircraft remain light, fuel-efficient, and withstand the rigours of flight. The heat treatment process enhances the properties of AMS 4091, ensuring that it can withstand even the most stringent engineering applications.

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