Order-disorder transformation in the Ni-4.49Â at.% Al alloy

The order-disorder transformation in the Ni-4.49 at.% Al alloy was studied using electrical resistivity measurements, microhardness measurements, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results confirmed the ordering behavior expected for Ni-Al dilute alloys and the suggested relation between resistivity changes and microhardness changes with anti-ferromagnetic spin ordering. The higher value obtained for the activation energy of vacancy migration was associated with a decrease in the Al concentration gradient near solute-depleted regions.