Superplasiticity in thermomechanically processed high magnesium aluminum-magnesium alloys

The elevated temperature deformation characteristics of two thermomechanically processed high magnesium, aluminum-magnesium alloys were investigated. the thermomechanical processing itself included warm rolling at 300 degrees C to 94% reduction. Subsequent treatements included anealling after rolling for either one-half hour or ten hours at 300 degrees C, or one-half hour at 440 degrees C. These annealing treatments resuted in varying degrees of recrystallization and grain growth and facilitated examination of the effect of grain size on the superplastic deformation characteristics of these alloys. Tension testing was conducted at strain rates ranging from 5.3x10(-5) to 5.3/10(-2) s-1 and temperatures varying from ambient to 300 degrees C. Materials in the warm rolled condition exhibited the highest strength at ambient temperature and were generally most superplastic at elevated temperature. An al-10%mg-0.5%Mn alloy exhibited elongation of approximately 400% at 300 degrees C.http://archive.org/details/superplasiticity00beckLieutenant Commander, United States NavyApproved for public release; distribution is unlimited