In the field of materials science, aluminum alloys have occupied an important position in many industries due to their excellent comprehensive properties. Among them, 2024 aluminum sheet is favored in high-end fields such as aerospace due to its high strength and good fatigue performance. Among the many tempers of 2024 aluminum alloy, T3 and T351 are often confused. Today we will analyze their differences in depth.
2024 aluminum alloy belongs to Al - Cu - Mg alloy. Copper (3.8 - 4.9%) in the alloy composition gives it high strength, while magnesium (1.2 - 1.8%) improves the processing performance and strength of the alloy to a certain extent. Due to its high strength and certain heat resistance (can be used for working parts below 150°C), it is often used to manufacture high-load parts such as skeleton parts, skins, bulkheads, wing ribs, wing spars, rivets, etc. on aircraft. However, its corrosion resistance is poor, and it is usually necessary to improve its corrosion resistance by anodizing, painting or adding aluminum coating on the surface.
2024 t3 alloy is a common processing temper. Its processing process is to first perform solid solution heat treatment, then cold working, and finally naturally age to a stable state. After T3 treatment, the aluminum alloy obtains higher strength. In the T3 state, the tensile strength of 2024 aluminum alloy can reach 483MPa (70,000psi) and the yield strength is 345MPa (50,000psi).
This high strength makes it ideal for structural parts that are subject to large tensile stresses, such as the wings and fuselage of aircraft, which are subject to huge aerodynamic and structural stresses during flight. 2024 aluminum alloy in the T3 state has good fatigue resistance, can maintain structural integrity under repeated alternating loads, and reduce the generation and propagation of fatigue cracks.
2024 t351 aluminum alloy is also based on solution heat treatment, followed by stretching to eliminate residual stress. The stretching amount is usually controlled between 1.5% and 3%, and then natural aging is performed. Compared with T3, the main feature of the T351 state is that the residual stress generated during the processing is eliminated.
The presence of residual stress may cause deformation or even cracking of parts during subsequent use, especially when subjected to complex stress or in specific environments. T351 treatment makes the stress distribution inside the material more uniform by precisely controlling the amount of stretching.
From the performance data, the tensile strength of 2024 aluminum alloy in T351 state is about 469MPa (68000psi) and the yield strength is 324MPa (47000psi). Although the strength value is slightly lower than that of T3 state, the material in T351 state performs better in dimensional stability.
This gives it a unique advantage in the manufacturing of some aerospace parts that require extremely high dimensional accuracy, such as high-precision aircraft engine parts, mounting brackets for avionics equipment, etc. These parts require strict control of dimensional tolerances during assembly to ensure the performance and reliability of the entire system.
Original Source:https://www.aircraftaluminium.com/a/aluminum-alloy-2024-t3-vs-t351.html
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