The Crystal Structure of Iron-Nickel Alloys

Crystal structure and density of a complete series of pure iron-nickel alloys. —Fourteen alloys were prepared by melting together Armco iron and electrolytic nickel, then swaging the castings and drawing and rolling into thin tapes. X-ray diffraction patterns were obtained with these, after various heat treatments. With from zero to 25 per cent Ni, the structure is chiefly body-centered-cubic, the parameter $a$ increasing from 2.872 × ${10}^{-8\mathrm{}}$ cm for pure iron to about 2.89 × ${10}^{-8\mathrm{}}$ cm. With from zero to 70 per cent Fe, the structure is chiefly face-centered-cubic, the parameter $a$ increasing from 3.510 for pure nickel to about 3.60 × ${10}^{-8\mathrm{}}$ cm. Around 30 per cent Ni, either structure is on the verge of instability and both or either may exist. Cold work tends slightly to increase the parameter. The densities of pure iron and nickel crystals come out 7.775 and 8.953 gm/${\mathrm{cm}}^3$, respectively.