Nanocrystalline Ni₃Al‐based alloys produced by mechanical alloying of Ni‐Al‐Co powders and consolidation

Abstract

In this work, preparation of nanocrystalline Ni3Al‐based alloys by mechanical alloying process followed by hot‐pressing consolidation is reported. Ni75Al20Co5 and Ni70Al25Co5 elemental powder mixtures were subjected to ball milling. Subsequently, the milling products were sintered at 1000 °C under a pressure of 7.7 GPa. The powders and the consolidated pellets were investigated by X‐ray diffraction. The results obtained show that the milling products were in both cases supersaturated solid solutions Ni(Al,Co) and that during the hot‐pressing consolidation they had transformed into nanocrystalline Ni3Al‐based intermetallic compounds. The microhardness of the produced Ni3Al‐based alloys is 918 HV0.1 in the case of Ni75Al20Co5 composition and 1033 HV0.1 in the second case. The density of compacted materials is close to the theoretical value and their open porosity is negligible. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Formation Mechanism of Nanostructured (Ni, Fe)3Al-Al2O3Nanocomposite and Its Characterization

“…Some processing problems may intensify these obstacles such as: the exothermic nature of formation of nickel aluminides and high difference in the melting point of Al and Ni. Microstructural modifications are processing routes which can overcome part of mentioned problems [3,4]. One of the effective techniques for preparing nanocomposite powders consisting of more than two phases is mechanochemical synthesis.…”

Thermodynamic analysis of (Ni, Fe)3Al formation by mechanical alloying

“…The alloys based on Ni-Al (such as Ni 3 Al) are particularly ideal for many special applications because of having a combination of privileged properties. The major barriers in the use of Ni 3 Al as structural materials are their low toughness and ductility at ambient temperature [2,3]. One of practical processing routes for the synthesis compounds and nanocomposites using the direct producing is mechanical alloying (MA) [4][5][6].…”