Effects of Annealing Treatments on Superplasticity in a Thermomechanically Processed Aluminum-10.2%Mg-0.52%Mn

摘要

This research follows previous thesis work by Becker and Mills on superplastic behavior of a warm rolled Al-10.2%Mg-0.52%Mn alloy. Elongations of up to 391% were reported to them for tension testing at 300 C and a strain rate of .0014/s. In this work, material was warm rolled at 300 C to 94% reduction and then subjected to one of five subsequent annealing treatments: 1 hour at 200 C, 10 hours at 200 C, 1/2 hour at 250 C, 1 hour at 250 C, or 1/2 hour at 440 C (to recrystallize the material). Tension testing at temperatures ranging from 300 C to 425 C was then conducted. Annealing below the rolling temperature enhances superplastic behavior when compared to the as rolled condition. For example, material warm rolled at 300 C with a strain rate of .0056/s gave a ductility of 572%. Annealing, however, for 1/2 hour at 440 C results in a recrystallized structure which is stronger than the as-rolled condition and less ductile when tested at 300 C.