Haoyan Diao
University of Tennessee Knoxville, Department of Materials Science, Graduate Student
ABSTRACT This paper concentrates on the study of the superplastic response of coarse-grained Al-Mg alloys under uniaxial tension at different temperatures (ranging from 400°C to 525°C) and strain rates (10-2 S-1, 10-3 S-1 & 10-4... more
ABSTRACT This paper concentrates on the study of the superplastic response of coarse-grained Al-Mg alloys under uniaxial tension at different temperatures (ranging from 400°C to 525°C) and strain rates (10-2 S-1, 10-3 S-1 & 10-4 S-1). The microstructures have been analyzed using optical (OM) and transmission electron microscopy (TEM). It has been observed that continuous re-crystallization occurs during hot deformation of the alloy at the temperature of 425°C and strain rate of 10-2S-1. At the temperature of 425°C and strain rate of 3.78×10-3S-1, this Al-Mg alloy has the maximum elongation to failure of 181%, which is sufficient for manufacturing of extremely complex shapes using superplastic forming technology. The constant strain rate sensitivity index m and TEM observations show that in this case deformation mechanism involved is dislocation glide. Recrystallization during the hot tension greatly enhanced the plasticity of the coarse-grained material at a strain rate of about 10-2S-1 and the maximum elongation changes as a function of the strain rate.
