Thermomechanical Processing of Aluminum Alloy 2519 for Grain Refinement andSuperplasticity

摘要

Thermomechanical processing (TMP) methods developed for Al-Mg and Al-Mg-Li alloyshave been modified and applied to the commercial 2519 Al-Cu alloy. The TMP included initial overaging and was designed to facilitate particle-stimulated nucleation (PSN) of recrystallization during controlled reheating intervals between successive rolling passes of the process. Effects of TMP variables were evaluated by tensile testing at temperatures ranging from 300-450 deg C. Strain rates varied from 6.7xl0 to the -5 power 1/s to 6.7xl0 to the -3 power 1/s. Also, microstructural analysis was conducted to determine the effect of the processing on the microstructure. The further evolution of microstructure during superplastic testing of the material was also assessed. Refinement to grain sizes below 10 microns by PSN was achieved. Superplastic ductility of 260 pct. elongation was limited by grain growth.