2124-T351 aluminum alloy is a heat-treatable Al-Cu-Mg series alloy developed for applications requiring high strength, fracture toughness, and improved damage tolerance. Although it has a chemical composition similar to that of the 2024 alloy, its more tightly controlled levels of impurity elements such as iron and silicon provide more uniform mechanical properties and improved transverse performance, particularly in thick sections. The T351 temper indicates that the material has been solution heat-treated, stress-relieved by controlled stretching, and then naturally aged. In terms of strength, 2124-T351 offers high yield and tensile strength and is significantly stronger than 6061-T6 alloy. Although it may provide lower strength than artificially aged tempers such as 2124-T851 and 7075-T6, it can offer better ductility, fracture toughness, and damage tolerance.

In terms of corrosion resistance, 2124-T351 does not possess naturally high corrosion resistance due to its high copper content. Its use without surface protection is not recommended in humid, saline, or chemically aggressive environments. In this respect, it provides lower corrosion performance than 5xxx series alloys such as 5083 and lower-copper alloys such as 6061. Its coating capability is good, and it can be used with chemical conversion coatings, primers, paints, and protective anodizing treatments. In aerospace applications, appropriate surface treatments and protective coatings significantly improve the material’s resistance to environmental effects and extend its service life.

In terms of machinability, 2124-T351 provides good performance and is particularly suitable for precision machining operations. The reduction of residual stresses through controlled stretching in the T351 temper lowers the risk of warping and dimensional distortion during the machining of large and complex components. For this reason, the material is preferred for precision aerospace parts machined from solid sheet or plate. However, its bending and forming properties are limited. Although it may provide better formability than harder, artificially aged tempers such as T851, it is not suitable for sharp bends or operations requiring high deformation. Heavy forming operations are generally performed in softer tempers, followed by the required heat treatments.

In terms of weldability, 2124-T351 provides poor performance. Conventional fusion welding methods are generally not recommended due to the risk of hot cracking and the loss of strength that may occur in the weld zone. Although resistance or spot welding may be used in certain applications, rivets, bolts, and other mechanical fastening methods are more commonly preferred for critical structural joints. Its vibration and fatigue behavior is also very good due to its controlled microstructure and high damage tolerance. It therefore provides balanced performance in aerospace components operating under repeated and variable loads.

Applications include high-performance structural uses, particularly in the aerospace, space, and defense industries. It may be used in aircraft wing and fuselage structures, load-bearing plates, ribs, bulkheads, fittings, and precision structural components machined from thick plate. Compared with 2024-T351, it stands out with its more tightly controlled impurity levels and improved transverse mechanical performance. Compared with 2124-T851 and 7075-T6, it provides a balanced combination of strength, ductility, fracture toughness, and machining stability.

MATERIAL COMPOSITION STANDARDS

2124 T351 may be supplied in accordance with the following standards and material designations.
• 2124 T351 Sheet; ASTM B209/B209M, EN 2422, EN AW-2124, EN AW-AlCu4Mg1(A), UNS A92124
• 2124 T351 Plate; ASTM B209/B209M, EN 2422, EN 573-3, ISO AlCu4Mg1(A), UNS A92124
 

Characteristic Properties of 2124 T351:

• Strength: High
• Machinability: Good
• Weldability: Poor (Spot and resistance welding may be used in certain applications)
• Formability: Low-Moderate
• Corrosion Resistance: Poor-Moderate
• Heat Treatment: Yes
   

Some Well-Known Applications of 2124 T351:
Aircraft wing and fuselage structures,
Ribs, bulkheads, and load-bearing structural components,
Precision aerospace components machined from thick sheet and plate,
Military vehicle and defense-industry applications,
Structures requiring high fracture toughness and damage tolerance,
Machining applications requiring dimensional stability.
 

STOCK
2124 T351 is supplied in sheet and plate forms.

• Sheet
• Plate