Low temperature superplasticity (LTSP) at 250 °C and 1×10{sup}(-3)s{sup}(-1) was observed in the 5083 Al-Mg base alloy after thermomechanical treatments (TMT). With increasing TMT rolling strain, the high angle grain boundary fraction increased, more favorable for the further operation of grain boundary sliding and LTSP. The strong texture components and bimodal misorientation distributions present after TMT were not affected by static annealing at 250 °C, but evolved gradually into a random orientation distribution during LTSP straining from 30% to 100%. When the LTSP elongation was greater than 150%, the macro-deformation anisotropy R ratio would finally reach a stable level. It seems that the LTSP performance was controlled by a large fraction of high angle boundaries, but not by the special coincidence site lattice boundaries.
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