What is the primary reason for refrigerating 2017 and 2024 aluminum alloy rivets after heat treatment?

The primary reason for refrigerating 2017 and 2024 aluminum alloy rivets after heat treatment is to retard age hardening. When aluminum alloys are heat treated, they become more malleable and ductile, allowing for easier forming and installation of rivets. However, if the rivets are simply left at room temperature, they will begin to undergo age hardening, a process that causes them to lose that initial malleability and become harder and potentially brittle over time. By refrigerating the rivets, this aging process is delayed, preserving the desired properties for a longer period before they are used in assembly.

Understanding the importance of refrigeration in this context highlights the necessity of controlling the alloy's properties to ensure optimal performance in aircraft structures. Proper care and handling of these rivets are crucial since their structural integrity directly affects the overall safety and longevity of the aircraft they are used in.