Microstructure and texture evolution of the cold-rolled AZ91 magnesium alloy strip under electropulsing treatment

The effect of electropulsing treatment (EPT) on the microstructure and texture evolution of the cold-rolled AZ91 magnesium alloy strip was investigated using X-ray diffraction (XRD) and electron backscattered diffraction patterns (EBSD). The results indicated that EPT accelerated tremendously the recrystallization behaviour of the cold-rolled AZ91 magnesium alloy strip at a relatively low temperature within a short time of 7 s. It also suppressed precipitation of β-Mg17Al12 phase, compared with conventional heat treatment. The recrystallized grains favourably weakened the intensity of the basal texture. A mechanism for rapid recrystallization process during EPT was proposed based on the enhancement of nucleation rate and atomic diffusion resulting from the coupling of the themal and athermal effects.

Research highlights▶ EPT induced recrystallization of cold-rolled AZ91 strip, and suppressed the precipitation of β-Mg17Al12 phase in the (-Mg matrix, at a relatively low temperature within a short time of 7 s. ▶ The extent of EPT induced recrystallization increased gradually with frequency, and the recrystallized grains favourably weakened the intensity of the basal texture until the full recrystallization was achieved. ▶ Compared with conventional heat treatment, EPT tremendously accelerated recrystallization process of the cold-rolled AZ91 due to the substantial increase in the atomic flux resulted from the coupling of the thermal and athermal effects.