## 1 Introduction  
Aluminum matrix nano-composites (AMNCs) are materials reinforced with metal or ceramic materials used to obtain nano-composite materials for different industrial applications. Al alloys are characterized as having a high strength/light weight, having resistance to the environment and having strong mechanical characteristics. These characteristics make them convenient for use in metal matrix composites (MMCs) [1]. Various reinforcement materials are utilized to enhance their mechanical and physical features. Improvements of these properties have been made in their manufacturing (AMNCs), which are utilized for high-technique engineering components, such as for aerospace, automotive purposes, and engineering shipbuilding. They are quite attractive for this purpose, as reinforced aluminum matrix composites with nano iron oxide (Fe\({}_{2}\)O\({}_{3}\)) are used in many aeronautical, automotive, etc., purposes due to their excellent efficiency and ratios of strength/weight and stiffness/weight [2]. AMNCs exhibit strong physical properties (electrical and magnetic properties) which enable them to be as lightweight as a multi-functional alloy. However, they do not have high wear resistance [3]. Mechanical properties of aluminum matrix composites, such as hardness, strength, modulus of elasticity and wear resistance, may be improved when the dispersed particles are nano-sized. Improvements in mechanical properties by using nanoparticles incorporated in aluminum matrices have been interesting in recent years [4]. However, the mechanical properties of AMNCs are affected by the manufacturing method used to synthesize nano-composites. Many different processing techniques have been used to manufacture composite and nano-composite materials involving melting casting and powder metallurgy [5]. However, the powder metallurgy technique appears to be the preferred method, owing to its ability to produce a homogeneous dispersion of additive materials into an aluminum matrix. In addition, the powder metallurgy technique gives better mechanical and physical properties. There are many advantages of powder metallurgy techniques, such as good bindings between the additive materials and the matrix, simple technique, easy control of the matrix's microstructure, near-net dimensions and shapes of the product and low cost. It is worth noting that products of powder metallurgy are affected by the particle size of additive materials (nano or micro) and their weight percentages. Various reinforcing materials may be used to produce aluminum composites or nano-composites for many applications, such as in aircrafts and electrical motors. Many investigations have been conducted in the same fields to obtain composites and nano-composites with unique properties, which are related to the size of the reinforcing materials, their dispersion into the matrix and the grain size of the matrix particles [6; 7; 8]. AA7068 alloy is used in different industrial engineering applications, including medical equipment, automobile parts and aerospace. The powder metallurgy technique is utilized to produce AA7068/MgO composites. Additive particles are mixed carefully to obtain a homogeneous dispersion into the matrix. The additive of MgO particles increases the mechanical properties of the product of composite materials, and, as a reinforcing material into the AA7068 alloy, it extensively increases wear resistance [9; 10]. In present times, there are many additive materials that are used to improve mechanical properties, such as Al\({}_{2}\)O\({}_{3}\), ZrO\({}_{2}\) and TiC, or electrical and magnetic properties, such as Fe\({}_{2}\)O\({}_{3}\), Fe\({}_{3}\)O\({}_{4}\), Ag and Co. In addition, other additive materials, such as Fe\({}_{2}\)O\({}_{3}\), ZnO, TiO\({}_{2}\), WO\({}_{3}\) and BiVO\({}_{4}\), which are known as semiconductor photo anode materials [11], are used to improve the efficiency of solar cells.