2. High-Energy Ball Milling Parameters in Production of Nanocrystalline Al Alloys

Alloying of elemental blends achieved through high-energy ball milling (HEBM) is referred to as mechanical alloying (MA), which is a solid-state powder processing technique involving the repeated deformation, fracture and welding of powder particles [1–4]. This technique was originally developed to produce oxide-dispersion strengthened (ODS) nickel and iron-base superalloys for aerospace applications [5]. Later, MA has been substantiated to be capable of synthesizing a variety of equilibrium and non-equilibrium phases, including nanocrystalline and amorphous materials. Recently MA has been demonstrated to be a most versatile and economical process for synthesis of nanocrystalline materials, due to its simplicity, low cost, and ability to produce large amount of material [1–4, 6]. Historically, from the point of Al based alloys, MA was used to produce dispersion hardened Al alloys [7–9]. Commercial production of Al alloys by ball milling was first reported by INCO alloys in year 1989 [10].