Texture gradient evolution in Al-5%Ca-5%Zn sheet alloy after tensile deformation at high superplastic strain rate

Abstract

Texture inhomegeneities have been found in many materials (l-9). Given the significant influence of texture in industrial processes like superplastic forming of complex-shaped components, it is important to study the evolution of texture gradients under different testing conditions, particularly at high strain rates. High strain rates are interesting for superplastic forming, since they enable faster production rates. The study of texture evolution allows, on the other hand, to go deeper into the microscopic mechanisms that occur during plastic deformation. It has been reported, for example, that initial texture gradients disappear when the material is tested superplastically (1). Grain boundary sliding (GBS) is commonly proposed as the microscopic mechanism responsible for superplastic deformation (10,ll). Therefore, grains would rotate independently of each other leading to a randomization of texture. However, the strengthening of certain preferred orientations during superplastic deformation (2) has suggested that GBS-based models are not always adequate to explain superplasticity.