Abstract

Mechanical alloying of Ni_3Al and Y_2O_3 added ODS Ni_3Al from elemental powders was investigated by the X-ray diffraction, differential scanning calorimeter, transmission electron microscopy and optical microscopy. The steady states of Ni_3Al and ODS Ni_3Al powders were reached after mechanical alloying with the condition of the ball-to-powder input ratio of 20:1 for 20 hours and 10 hours, respectively. The addition of nano-sized Y_2O_3 particles enhanced cold working and fracture, and subsequently accelerated MA of Ni_3Al powders. DSC results of MAed Ni_3Al powders showed four exothermic peaks at 140°C, 234°C, 337°C and 385°C. From the high temperature X-ray diffraction analysis, it was concluded that the peaks were resulted from the recovery solution of unalloyed Al in Ni, the formation of intermediate phase NiAl, and LI_2 ordering of MAed Ni_3Al powders.