Nanocrystalline Ni3Al intermetallic produced by hot-pressing consolidation of mechanically alloyed powders

Abstract

In the present work bulk nanocrystalline Ni3Al alloys were produced by mechanical alloying of powdered Al3Ni or Al4Ni96 alloys mixed with Ni or Al respectively, followed by a hot-pressing consolidation. In the case of both mixtures a Ni(Al) solid solution was a product of ball milling. The powders of Ni(Al) were consolidated at 1000 °C for 180 s under the pressure of 7.7 GPa. The XRD investigations have revealed that during consolidation the disordered solid solution transforms into the ordered nanocrystalline Ni3Al intermetallic compound with an average mean crystallite size of ∼30 nm. The microhardness of the produced samples is 1033 and 1093 HV0.1 and is relatively high in comparison to literature data. The density of the obtained samples is close to the theoretical value of the Ni3Al intermetallic phase and the open porosity of the compacts is negligibly small.