Formation of NiAl intermetallic by gradual and explosive exothermic reaction mechanism during ball milling

NiAl intermetallic has been produced by mechanical alloying in a high energy vibrator mill using elemental Ni and Al powder mixture. The NiAl powders were formed in two ways. One by a gradual exothermic reaction mechanism during a long time continuous milling and the other by explosive exothermic reaction mechanism that occurred when opening the milling vessel to the air atmosphere after a short time milling. Prolonged milling for both cases resulted in change of morphology and refinement of grain size down to nano scale.