Development of Heterogeneous Nano-Structures in a Cu-Zn Alloy with Different Initial Textures

The effect of initial texture on the formation of deformation twins and its impact on the final heterogeneous nano-structure (HN-structure) and mechanical properties of a Cu-Zn-Sn alloy with an extremely low stacking fault energy during cold rolling were systematically investigated. Specimens with an accumulation of 〈111〉 along the normal direction (ND) were prepared and cold-rolled up to 90% reduction in thickness. Two different rolling directions (RD) were applied: one with a high accumulation of 〈211〉 along RD (211 specimen) and another with a 〈110〉 orientation (110 specimen). The 211 specimens exhibited higher volume fractions of twinned grains in the early stages of rolling (∼50% reduction) than the 110 specimens. In the later stage of rolling (60∼90% reduction), the HN-structure consisting of deformation twin domains, lamellar grains and shear bands was well developed in both specimens. However, the 〈211〉 specimen exhibited a higher fraction of twin domains with {111}〈211〉 orientation, whereas the 〈110〉 specimen contained more {111}〈110〉 twin domains. The highest strength-ductility balance was achieved at an 80% reduction, with the 211 specimen exhibiting a higher strength-ductility balance. The higher strength of the 211 specimen is attributed to the higher fraction of {111}〈211〉 twin domains, which offer greater resistance to plastic deformation compared to {111}〈110〉 twin domains.