Effect of stacking fault energy on mechanical properties of nanostructured FCC materials processed by the ARB process

In the present work, the effect of stacking fault energy on the mechanical properties of aluminum, copper, and brass fabricated via the accumulative roll bonding (ARB) process was investigated. Mechanical properties and microstructural evaluation of the samples were evaluated by tensile and hardness tests and also transmission electron microscopy (TEM). It was found that differences in the mechanical properties during the ARB process of aluminum, copper, and brass were completely related to their stacking fault energies (SFEs). The tensile strength of the brass was much higher than that of the copper and aluminum at all ARB cycles. This was attributed to smaller grain size, higher dislocation density and higher twin density of the brass during the ARB process. It was realized that the ductility of the brass was higher than that of the copper for all ARB cycles. This was related to higher twin density in the brass sample. The hardness results were indicated that the saturation of dislocation density that occurred at the second, third, and fifth cycles for aluminum, copper, and brass, respectively. In fact, when the SFE was decreased, the number of ARB cycles for saturation of hardness increased.