Formation of NiAl intermetallic by gradual and explosive exothermic reaction mechanism during ball milling

Effect of CNT addition approach on the microstructure and properties of NiAl-CNT nanocomposites produced by mechanical alloying and spark plasma sintering

“…The reason for the disappearance of the Al XRD peaks can be either the crystallite refinement of Al or the atomic scattering factors of the elements. Considering XRD results it can be concluded that NiAl has been synthesized by gradual diffusion of elements through the point defects, dislocations and the fine lamellar structure induced by MA as mentioned by previous researchers [7]. According to the literature the synthesis of NiAl by MA process may accomplish also through self-propagating or diffusional mechanism depending on the milling conditions [8].…”

“…Several methods such as grain refinement [3], second-phase strengthening [5] and alloying [6] have been offered to overcome this limitation. High energy ball mills have been used for mechanical alloying (MA) as a production method to synthesize and modify intermetallic compounds like NiAl [3,7]. It has been stated by several researchers that during MA of Ni and Al powder mixtures, NiAl intermetallic compound formation occurs either gradually along milling time, or suddenly through a mechanically self-propagating reaction (MSR), which occurs after a certain time of MA called ignition time [7,8].…”

“…High energy ball mills have been used for mechanical alloying (MA) as a production method to synthesize and modify intermetallic compounds like NiAl [3,7]. It has been stated by several researchers that during MA of Ni and Al powder mixtures, NiAl intermetallic compound formation occurs either gradually along milling time, or suddenly through a mechanically self-propagating reaction (MSR), which occurs after a certain time of MA called ignition time [7,8]. In the last decade MA has been widely used for the fabrication of intermetallic matrix composites containing ceramic or metalloid particles [9e11].…”

Effects of processing and powder size on microstructure and reactivity in arrested reactive milled Al+Ni

“…The powder is processed through repeated impacts of a "grinding" media usually made from elastically deforming spherical balls enclosed in a sealed container that produces materials with highly refined microstructures, enhanced strength or meta-stable phases [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. This technique has been shown to synthesize intermetallic compounds resulting from gradual and explosive formation at the grain level [3,4,6,[9][10][11][12][13]. A self-sustained hightemperature synthesis (SHS) of intermetallics may release large amounts of heat during intermetallic phase formation on the order of that released by explosives [17].…”

“…A self-sustained hightemperature synthesis (SHS) of intermetallics may release large amounts of heat during intermetallic phase formation on the order of that released by explosives [17]. The gasless reaction from reactive milled (RM) experiments forming nickel-aluminides [3,4,6,[8][9][10]12,15,16,18], titanium-based alloys [5] and combustion reactions in metal-metal-oxides [11,13,14] in a ball-mill are several examples of materials that exhibit SHS.…”