Mechanical Alloying: A Novel Technique to Synthesize Advanced Materials

Abstract

<jats:p>Mechanical alloying is a solid-state powder processing technique that involves repeated cold welding, fracturing, and rewelding of powder particles in a high-energy ball mill. Originally developed about 50 years ago to produce oxide-dispersion-strengthened Ni- and Fe-based superalloys for aerospace and high temperature applications, it is now recognized as an important technique to synthesize metastable and advanced materials with a high potential for widespread applications. The metastable materials produced include supersaturated solid solutions, intermediate phases, quasicrystalline phases, amorphous alloys, and high-entropy alloys. Additionally, nanocrystalline phases have been produced in virtually every alloy system. Because of the fineness of the powders, their consolidation to full density without any porosity being present is a challenging problem. Several novel methods have been developed to overcome this issue. Powder contamination during milling and subsequent consolidation constitutes another issue; this can be resolved, though expensive. A number of applications have been developed for these novel materials. This review article presents an overview of the process of mechanical alloying, mechanism of grain refinement to nanometer levels, and preparation of materials such as nanocomposites and metallic glasses. The application of mechanical alloying to synthesize some advanced materials such as pure metals and alloys, hydrogen storage materials, and energy materials is described. The article concludes with an outlook on future prospects of this technique.</jats:p>

Structure and mechanical behavior ofin situdeveloped Mg2Si phase in magnesium and aluminum alloys – a review

“…This technique is also used to synthesize supersaturated solid solutions, intermediate phases, quasi-crystalline phases, amorphous alloys, and high-entropy alloys. 48 This technique is also used to produce very ne crystallite sizes down to the nanoscale. 49 There are very few published reports concerning the formation of an Mg 2 Si phase by mechanical alloying at present.…”

“…49 There are very few published reports concerning the formation of an Mg 2 Si phase by mechanical alloying at present. Niu et al 48 formed the Mg 2 Si phase via a mechanical alloying method using a high-energy planetary ball mill. Stoichiometric compositions of magnesium and silicon powders are milled at 250 RPM with a ball to powder ratio of 20 : 1 for 30 hours.…”

Spark Plasma Sintering of Titanium Aluminides: A Progress Review on Processing, Structure-Property Relations, Alloy Development and Challenges

“…The process of mechanical alloying (MA) involves loading of PA or elemental powders inside a high energy ball mill and the usage of grinding media to repeatedly cold weld, fracture and reweld powder particles [41]. Parameters including time, speed and BPR [42] are optimised to control and balance the resultant powder particle sizes.…”

“…PCA are inorganic compounds [43] often used in MA of ductile metals to prevent agglomeration of powder particles. According to Suryanarayana [41], adding 1-2 wt. % of PCA can prevent excessive cold welding or agglomeration of the individual powders on the grinding media and the milling vessel.…”

Peculiarities of Refractory Borides Formation during Mechanical Alloying IV-V Group Transition Metals with Boron in Planetary Mill

“…This can be performed with the help of a planetary mill where extremely high centrifugal forces appear under milling due to the disk and the vials rotation in the counter direction. Milling process of a solid state powder, where the powder particles are subjected to high energetic impacts by the balls in a vial, which involves repeated cold welding, fracturing, and rewelding of powder particles, is called mechanical alloying [3]. Numerous studies have been devoted to production of transition metal borides using a mechanical alloying [4][5][6][7][8][9][10][11].…”