The 2024 T651 aluminum alloy is a high-strength, wrought aluminum alloy widely used in the aerospace and defense industries. Its primary component is aluminum, with copper as the main alloying element, typically in the range of 3.8–4.9%. It also contains small amounts of magnesium and manganese to enhance its mechanical properties. The T651 temper indicates that the alloy has undergone a T6 heat treatment followed by stress relieving through stretching, which improves dimensional stability and machinability.

Due to its high tensile and yield strength, 2024 T651 is one of the most commonly used aluminum alloys in structural applications, often favored over steel for weight-sensitive designs. However, its strength comes with the trade-off of reduced corrosion resistance, which is why it is typically used with protective coatings or anodizing. It offers good machinability, though it is difficult to weld, and is usually joined using mechanical fastening methods such as riveting. These characteristics make 2024 T651 a preferred material for aircraft structures, automotive components, and other high-performance engineering parts.