Effect of thermo-mechanical treatment on cube texture in aluminum foils for electrolytic capacitor

Abstract

The present study was carried out to clarify the effect of condition of thermo-mechanical treatment (partial annealing and additional rolling) on behavior of cube texture in high purity aluminum foils for electrolytic capacitor. Foils were partially annealed at 503, 523 and 543 K and additionally rolled to 12, 17 and 22% reduction. They were finally annealed at 573 K. All foils were evaluated by SEM-EBSP method. It was elucidated that the foil partially annealed at 523 K and additionally rolled to 17% reduction, had larger area fraction of cube-oriented grains than the other foils after final annealing. From the examination of that, it was concluded that the distribution and diameter of cube-oriented grains depended on the partial annealing temperature and that grain growth in final annealing was affected by the residual strain in grains attributed to the degree of reduction of the additional rolling. It was considered that the optimized condition of thermo-mechanical treatment enhanced growth of cube-oriented grains and suppressed the other grains. On the basis of the theory to bulge nucleation, the critical diameter of growth of cube-oriented grains was estimated. The estimated diameter was compared with the distribution of the measured diameter of cube-oriented grain. The result explained well the dependence of the area fraction of cube-oriented grains on foils with different conditions of thermo-mechanical treatment after final annealing.