Aluminum 2024 is a high-strength aluminum alloy widely used in aerospace and other industries requiring durable, lightweight materials. As an aluminum-copper-magnesium alloy, do you know everything about aluminum alloy 2024? If you don’t, this article provides 2024 aluminum properties, processes, pros, applications & compositions.
What’s 2024 Aluminum Alloy?
Aluminum 2024 is a copper-magnesium alloy of aluminum that is often used in aircraft structures. It provides an excellent strength to weight ratio that makes it ideal for applications where lightweight yet durable materials are required like in the aerospace industry. Aluminum 2024 contains between 3.8-4.9% copper and a maximum of 1.5% magnesium, which contribute to significantly higher strength than pure aluminum or other common aluminum alloys like 6061. The addition of copper and magnesium improves the alloy’s strength through precipitation hardening, allowing it to withstand higher stresses. However, aluminum 2024 is not as corrosion resistant as other alloys and requires protection. Its excellent mechanical properties make it a great option when high strength is prioritized over corrosion resistance.
What Are The Properties Of 2024 Aluminum?
Composition: Aluminum (93-95%), copper (3.8-4.9%), magnesium (0.1-1.5%)
Density: 2.77 g/cm3 (aluminum’s density is 2.7 g/cm3 for comparison)
Melting Point: Approximately 660°C or 1220°F
Tensile Strength: Approx. 485 MPa or 70 ksi (depending on temper/conditioning process)
Yield Strength: Approx. 420 MPa or 61 ksi
Elongation: Around 5-10%
Hardness: 95-120 HV (Brinell hardness values)
Fatigue Strength: High cyclic strength, up to 200 MPa
Modulus of Elasticity: Around 73 GPa or 10.6 million psi
Thermal Expansion: 23-24 μm/m°C or 13 μin/in°F
Thermal Conductivity: Around 100-180 W/mK
Electrical Conductivity: Significant at 60-65% IACS
Corrosion Resistance: Good, protected by aluminum oxide layer
Machinability: Easy to machine with good surface finish
Weldability: Can be welded, especially for thin sheets and plates
The Heat Treatment Process For 2024 Aluminum
2024 aluminum is a heat-treatable alloy, meaning its properties can be significantly improved through precise heating and cooling steps. The most common heat treatment is solution heat treatment plus aging.
Solution Heat Treatment:
The aluminum is uniformly heated to a temperature between 775-815°F, above the solvus temperature. This causes copper-containing precipitates to dissolve back into the aluminum matrix. The alloy is then rapidly quenched (cooled) in water or air to retain the high-temperature phase.
Aging:
The quenched aluminum is then reheated to 150-200°F for a specific time period. This promotes nucleation and controlled growth of strengthening precipitates within the aluminum grains. As copper comes out of solution again as fine particles, strength is increased via precipitation hardening.
What Are The Advantages Of 2024 Al Alloy?
High strength-to-weight ratio – 2024 aluminum is very strong for its weight, making it a good option for applications where lightweight strength is important.
Amenable to heat treatment – The alloy’s properties can be further enhanced through precipitation heat treatments, increasing its strength.
Good fatigue strength – 2024 aluminum maintains its strength even after repeated cyclic stresses, making it durable for long-term use.
Excellent machinability – The alloy can be readily machined, formed, and fabricated using standard techniques.
Wide range of forming capabilities – 2024 aluminum can be extruded, rolled, drawn, or forged into various shapes.
Corrosion resistant – When properly protected with a coating or treatment, 2024 aluminum holds up well against corrosion from weathering or other environments.
Low cost – 2024 aluminum offers good performance characteristics at a relatively low cost compared to other high-strength metals like steel or titanium alloys.
Recyclable – Any scrap or recycled 2024 aluminum can easily be remelted and reused for new products.
What Are The Applications Of 2024 Aluminum?
Aircraft structures – 2024 aluminum is widely used in airframe construction like fuselages, wings and wing components due to its high strength to weight ratio.
Aerospace components – Parts like landing gear, disk brakes, engine valves and auxiliary equipment for planes and spacecraft utilize 2024 aluminum.
Automotive applications – Some high-end cars use 2024 aluminum for weather resistance body panels, hoods and trunk lids to reduce overall weight.
Marine vessel construction – Its corrosion resistance and durability make 2024 alloy useful in ship and boat building for hulls and superstructures.
Bicycles and cycling gear – Frames, wheels, pedals and other bicycle parts employ 2024 aluminum to achieve lightweight performance.
Industrial equipment – Machinery, pumps, valves and other fabricated metal products may incorporate 2024 aluminum.
Pressure vessels – Its ability to withstand internal pressure enables uses like compressed air tanks.
Defense applications – Military equipment such as artillery shells, missiles and armored vehicles take advantage of 2024 aluminum.
General fabrication – The alloy is also stocked as sheet, plate and bar materials for general machining and fabrication purposes across many industries.
Chemical Compositions of Aluminum 2024
2024 aluminum alloy gets its strength primarily from its copper content, which ranges from 3.8% to 4.9% by weight. Smaller amounts of other elements like magnesium, manganese and others are also added to 2024 aluminum. Magnesium is typically present at 0.1-1.5% to help improve strength through precipitate hardening. Manganese is around 0.3-1.0% where it aids in controlling grain structure. Silicon generally makes up no more than 0.5% and iron content is typically less than 0.5%. Small trace amounts of other elements like chromium, zinc and titanium sometimes exist too at levels under 0.25%. The balance is aluminum, which comprises anywhere from 93-95% by weight of the total composition. This precise mix of major alloying elements like copper and minor additive metals is what differentiates 2024 aluminum and gives it its unique blend of mechanical properties suitable for high-strength applications.