During the past few decades, ultrafine-grained materials (UFG) have experienced rapid development. Enhanced mechanical and surface properties, such as strength, ductility and erosion-corrosion (E-C) resistance by refining the grain to ultra-fine/nanometer size has been achieved. The equal channel angular pressing (ECAP) is a popular severe plastic deformation (SPD) method to fabricate UFG bulk materials. In this research, the E-C behavior of commercial annealed pure copper subject to four passes of ECAP have been investigated. Hardness measurement of the copper specimen after four passes of ECAP showed an increase of 200% on the hardness value as compared with annealed condition. Simulated seawater was used as an E-C medium. The effect of different E-C parameters such as time, slurry flow velocity, impact angle, and solid particle concentration on ECAP process is studied. The results showed that ECAP enhances the E-C resistance of copper, and this behavior improves with increasing the pass number. Generally, a 30% rise in resistance to E-C was achieved after four ECAP passes as compared to coarse grain copper for the parameters studied in this work. Optical microscopy was used to examine the microstructure and material removal mechanism of the annealed copper. Scanning electron microscopy (SEM) was used to validate the reduction of grain size due to ECAP process. Furthermore, examination of the surface roughness of the copper at different ECAP passes showed that for the same E-C condition the increment of ECAP passes leads to a smoother surface.

This review is provided with a detailed overview of common reinforcement and inspection techniques for producing reinforced composite materials. This study focuses on the state of the art for how used carbon nanotubes (CNTs) as a reinforced material to obtain micro-composite and nano-composite materials. On the other hand, up to now, the major problem is to get a uniform dispersion of the CNTs in the wanted reinforced composite material. So, this review paper emphasizes on several techniques which are utilized for improving the dispersion of CNTs in a metallic powder, such as copper (Cu), aluminum (Al), and magnesium (Mg) as matrix composites. Furthermore, this review presents two different experimental techniques (destructive testing and non-destructive testing) with the purpose of detection of CNTs dispersion in the reinforced composite material. As a result, this review is a helpful tool for all scientists for deciding which technique is more suitable for their research composite materials.