Mechanical alloying of the Ti-Al system

Microstructural aspects and positron annihilation study on solid state synthesis of amorphous and nanocrystalline Al60−xTi40Six alloys prepared by mechanical alloying

“…Thus, the microstructure at this stage of milling (20-30 h) seems to comprise a mixture of amorphous and nanocrystalline phase, possibly, Al 3 Ti. It may be mentioned that intermetallic Al 3 Ti has a strong negative enthalpy of mixing (DH m = À39.43 kJ/mol [19]) and is known to easily form by mechanical alloying [20]. In the present study, continued milling of the Al 50 Ti 40 Si 10 blend up to 30 h did not produce any significant change in the phase distribution or microstructural constituents.…”

Study on solid-state reactions of nanocrystalline TiAl synthesized by mechanical alloying

“…After 60 h of milling time the XRD pattern indicates the formation of a new phase as a result of crystallization of amorphous phase. The XRD pattern can be ascribed at the same time, either to a disordered form of Ti 3 Al structure due to the absence of superlattice reflections or to a supersaturated Ti(Al) solid solution, ␣, with more than 30 at.% Al content, as suggested by Guo et al [13]. Assuming the similarity between the new phase and ␣ structure, it could be a supersaturated Ti(Al) solid solution with hcp structure.…”

Mechanical Alloying: For Formation of Nanocomposite WC/MgO Materials

“…Furthermore, the powder yield is low as many particles get adhere to the milling balls and vial, which is difficult to be detached. There are two possible methods to prevent the combustion reaction and the severe welding, one is to lower the temperature of the milling vial (Jang & Koch, 1990;Guo et al, 1990;Fecht et al, 1990), and the other is to add stearic acid as a process control agent (PCA) to the reactant powders (Suryanarayana & Sundaresan, 1991;Wang et al, 1991). The effects of stearic acid on the ball milling process of CuO-Ca/Ni, Ti-BN and Al-Mg systems had been investigated by Schaffer, Byun and Lu respectively (Schaffer & McGormick, 1990;Byun et al, 2004;Lu & Zhang, 1999).…”