Effect of stacking fault energy on deformation texture development of nanostructured materials produced by the ARB process

Abstract

In this study, the effect of stacking fault energy on deformation texture development of nanostructured face-centered cubic (FCC) materials fabricated via accumulative roll bonding (ARB) process was investigated. Textural evolution was evaluated using X-ray diffraction and microstructural observation was evaluated by transmission electron microscopy (TEM). It was found that in the copper and brass sample, unlike the aluminum sample, the intensity of Brass component remarkably increased at the high deformation, resulting from the slip of dislocations, mechanical twinning, and even shear banding. The main difference between aluminum (representing the high SFE), copper (representing the medium SFE) and the brass (representing the low SFE) textures lied in the prominence of the Copper component in the aluminum (at all cycles) and copper (at low and high cycles) texture and the absence of this component in the brass (at all cycles) and copper (at medium cycles) texture. In fact, as the SFE decreased, the Copper component replaced by a Brass orientation. Also it was realized that the SFE plays a decisive role in the occurrence of texture transition of FCC materials. On one hand, the continuous recrystallization occurred in the aluminum sample and this phenomenon led to decrease in the orientation intensities of β-fiber. On the other hand, the discontinuous recrystallization occurred in the copper and brass sample and this phenomenon led to decrease in the orientation intensities of β-fiber, Copper, and Dillamore textures. In fact, as the SFE decreased, the stacking faults became wider, making cross-slip more difficult. Hence, mechanical twinning was favored. Therefore, the possible restoration mechanism in the copper and brass was discontinuous recrystallization.