I have an application that involves forming 2024 aluminum in the T42 state. I need to determine [approximate] the amount of elastic stretch vs yield once the yield point has been exceeded. In other words, once beyond the yield point, how much of the strain results in addional yield, as opposed to additional elastic strain. As near as I can tell so far this will have to be determined empirically. Additionally, I need to get a handle on the degree of work hardening [relative to the T value] that occurs with each bend. Any information provided is greatly appreciated.