In the designation of 2017-T36 aluminum alloy, what does the number 2 indicate?

In the designation of 2017-T36 aluminum alloy, the number 2 indicates that the primary alloying agent used is copper. Aluminum alloys are categorized by a four-digit numerical system, where the first digit represents the major alloying element. In this case, the "2" signifies that copper is the principal alloying element in this particular alloy series.

The letter "T" that follows the number indicates that the alloy has undergone a specific heat treatment process, which in this case refers to a temper designation (the "T3" indicates a solution heat-treated and artificially aged state). The final digits provide information about the specific treatment and mechanical properties of the alloy.

This classification system is critical for identifying the characteristics and applications of different aluminum alloys in aviation and other industries. Understanding these designations is essential for selecting the right material for various structural applications.