Effect of long-range ordering in a Ni-Mo alloy on its mechanical properties and corrosion resistance

Long-range atomic order do not vitally degrade the mechanical strength and corrosion resistance of certain alloy systems such as Ni-Mo alloy. Conversely, it may even have some beneficial effects on properties particularly mechanical strength. The respective values of Mo concentrations from the concentration profiles of alloys derived by in-situ fracture and sputtering of aged specimens in an Auger spectrometer. Ordering in the vicinity of grain boundaries is occurred due to a discontinuous mechanism resulting in an alternating lamellae of Ni₄Mo and a Mo-depleted solid-solution. Most of the metal wastage appeared to be due to intergranular attack at the onset of the discontinuous grain boundary reaction. There is also a possibility of using single crystals of ordered alloys in certain applications and identify the means for modifying the structure of grain boundaries to suppress the undesirable discontinuous ordering reaction.