Improved mechanical property and internal friction of pure Mg processed by ECAP

Equal channel angular pressing was performed on the extruded pure Mg. The elongation to failure of the ECAPed pure Mg is enhanced to 27% without sacrificing the strength, which is mainly resulted from both the effective refinement of grain size and the weakening of the basal plane texture. The internal friction mechanisms of magnesium at room and elevated temperature were studied by dynamic mechanical analyzer (DMA). The strain independent internal friction is increased after ECAP processing, while the strain dependent part is obviously decreased. Three internal friction peaks were observed in the temperature dependent internal friction curves. The activation energy is 105kJ/mol for P₁ peak, which may be related to the basal dislocation glide controlled by climb of jogs and diffusion of vacancies along dislocations. The activation energy of P₂ peak is in the range from 95 to 181kJ/mol, and this obviously broadened peak is associated with grain boundary relaxation. The P₃ peak is related to recrystallization.