An investigation of the effect of Oxygen on the behavior of 65 Ni-2Mo-Fe alloy

The effect of oxygen on the capability for secondary recrystallization and the magnetic properties of the 65Ni-2Mo-Fe alloys have been studied. From the X-ray diffraction and the microscopic experiments, it was found that when the content of oxygen reached 0.03 percent in the alloy a strong capability for second recrystallization was attained. In correspondence with the big secondary grains a maximum permeability of the alloy with a value as 200 × 10⁴G/oe could be obtained. At the same time, we proposed a possible mechanism of the action of oxygen: With an increase of the oxygen content in the alloy, the accumulation of the oxygen introduced a fairly big strain energy. In order to lower the increased free energy due to this kind of size effect, an excess amount of vacancies was produced, that in turn promoted the secondary recrystallization, improved the recrystallized structure and evidently raised the magnetic permeability. Our experiments on electrical resistivity and the quantitative estimate of the amount of the strain energy induced by various forms of the oxygen present supported the views presented in our paper.