Improved stretch formability of AZ31 sheet via texture control by introducing a continuous bending channel into equal channel angular rolling

Abstract

This work aimed to alter the texture components and enhance the stretch formability of rolled AZ31 sheets by developing the rolling technology. In this study, a continuous bending channel was introduced into an equal channel angular rolling apparatus and a new rolling technology was successfully developed. Microstructure evolutions during hot-rolling, equal channel angular rolling and subsequent continuous bending were investigated. Results showed that hot-rolling generated a strong basal texture component. Single pass equal channel angular rolling cannot eliminate the basal texture component, while can greatly weaken basal texture intensity. After continuous bending, basal texture component was almost eliminated. Meanwhile, a strong c-axis//RD texture component and a weak double-peak texture component with symmetrical splitting of the {0002} basal texture were formed. After recrystallization annealing, symmetrical double-peak texture whose {0002} pole peak located at about 40° from normal direction towards the rolling direction was enhanced with the disappearance of c-axis//RD texture. The AZ31 sheets with double-peak texture exhibited excellent stretch formability at room temperature (with an Erichsen value of 7.4 mm). Finally, the relevant mechanisms were discussed.