On the Texture Weakening During Electropulse Annealing Treatment of Mg-1Ce Alloy: The Role of Nucleation and Nucleus Growth

Mg-1Ce alloys were pre-rolled at room temperature to various reductions to achieve different as-rolled microstructures. The deformed materials were then treated with a pulsed electric current (electropulse treatment, EPT) to study the effect of the as-rolled microstructure on the recrystallization texture formation. The experimental results show that an optimum window exists for pre-rolling reductions, within which the as-rolled microstructures and sharp basal textures obtained will evolve into fine recrystallized grains and weak textures during the subsequent EPT. Microstructure analysis indicates a competition between two processes, the nucleation and the nucleus growth, in contributing to the texture weakening of the alloy. While both the application of pulsed electric current and the increase in the pre-rolling reductions could strengthen the advantage of the nucleation rate of the non-basal nuclei over those with basal orientations, the contribution from nucleus growth depends mainly on the available deformed basal-oriented matrix, which decreases with increasing pre-rolling reductions. The results of the present study might provide useful guidance for the optimization of process parameters in the future application of the ‘pre-rolling + EPT’ technique on the Mg alloy sheet.