EBSD characterization of nano/ultrafine structured Al/Brass composite produced by severe plastic deformation

Abstract

In the present work, nano/ultrafine structured Al/Brass composite was produced by accumulative roll bonding (ARB) up to eight cycles. The evolution of grain refinement and deformation texture and their effect on the mechanical properties were investigated. It was observed that by increasing the ARB cycles, due to the difference in flow properties of the metal constituents, brass layers necked, fractured and distributed in aluminum matrix. After eight cycles, a composite was produced with almost homogeneous distribution of brass fragments in aluminum matrix. Microstructural characterization by electron backscatter diffraction (EBSD) revealed the formation of bimodal structure consisting of equiaxied grains with an average size of ~120 nm and elongated grains after eight cycles, which was attributed to the occurrence of redundant shear and recrystallization. The crystallographic texture results indicated that the major texture components in the aluminum matrix were Brass {011}, S {123}, Goss {011} and Rotated Goss {011}. Moreover, it was concluded that Goss {011} and Rotated Goss {011} components appeared for high number of ARB cycles due to the adiabatic heat during ARB processing. The tensile strength of Al/Brass composite reached 330 MPa, which was 4.23 times and 1.83 times higher than those of annealed aluminum and monolithic aluminum, respectively. Finally, fracture surfaces of samples were studied, using field emission scanning electron microscope (FESEM), to reveal the failure mechanism.