Low temperature super ductility and threshold stress of an ultrafine-grained Al-Zn-Mg-Zr alloy processed by equal-channel angular pressing

Low temperature tensile and impression creep tests were carried out on an ultrafine-grained 7xxx series Al-4.8Zn-1.2 Mg-0.14Zr (wt%) alloy, which can be deformed for maximum elongation of about 200% at 150 degrees C. The characteristics of the deformation process, such as the strain rate sensitivity (SRS) and activation energy (Q) were determined by considering also the effect of threshold stress. Relatively high SRS of similar to 0.35 and low activation energy of similar to 92 kJ/mole were obtained, confirming the super ductility of the investigated ultrafinegrained alloy in the low temperature region between 140 and 160 degrees C.

Automated summary

The study found that the ultrafine-grained alloy exhibited super ductility in the low temperature range, with relatively high strain rate sensitivity and low activation energy.