Phase transformations study on Ni75Al25 and Ni50Al50 during mechanical alloying and sintering

In the present work we study the phase transformations taking place by mechanical alloying in the Ni-Al system and with further consolidation by sintering at high pressures with the aim of maintaining nanometric grain size. Different phase transformations were observed during milling, a Ni(Al) saturated solid solution for Ni-25 at.%Al and the formation of the intermetallic compound for Ni-50 at.%Al. Amorphization and recrystallization was also observed after prolonged milling. These phases remain after sintering with nanometric grain size and very high values of hardness. (C) 2006 Elsevier B.V. All rights reserved.