Which rivet type can be used as received without further treatment?

The correct answer is 2117-T3 rivets, which are often used in aircraft structures. This specific alloy is treated and can be utilized in its received state without the need for additional heat treatment.

2117-T3 rivets are made from an aluminum alloy that is thermally treated to achieve a balanced combination of strength and ductility. The T3 temper signifies that the material has been solution heat-treated and then artificially aged, making it ready for immediate use in applications requiring effective joining techniques without further processing.

In contrast, the other options represent alloys that typically require further processing or heat treatment to achieve acceptable mechanical properties for structural applications. The 2024-T4, for example, needs to be heat-treated to reach its full strength, while both 6061-T6 and 7075-T6 also require specific heat treatment for optimal performance. These distinctions highlight the readiness of 2117-T3 rivets for immediate application in structural work, making them a preferred choice for many assembly processes in aerospace industries.