Effect of Mechanical Alloying and Heat Treatment Process on the Phase Transformation of Ni-Cr-Al Powders Mixture

In this study Ni50Al50 and Ni5Cr5Al50 were undergone mechanical alloying and heat treatment. The structural changes of powder particles during processes were studied by X-ray diffraction (XRD). It appeared that there are different phase transformations after both treatments: Ni50Al50 formed a nanocrystalline, orderly NiAl intermetallic compound; on the other hand (NiCr)Al intermetallic which itself was produced from Ni50Cr5Al5. The morphology and cross sectional area of the powder particles were characterized by scanning electron microscopy (SEM). The conclusion was that during initial stages of milling the layers of Cr, Ni, and Al are produced which subsequently are transformed into the final product upon further treatments.