Mossbauer experiments on iron-nickel alloys with mixed α and γ structures

The results are reported of some Mössbauer experiments on the α phase of FeNi alloys around 30% Ni, in which a partial transformation occurred. The experiments, performed on vacuum melted alloys prepared with special care to obtain very homogeneous solid solutions, show significant broadening of the lines when partial martensitic transformation is produced by cooling to low temperatures. These effects can be explained by the presence of very strong internal stresses associated with the partial transformation. The corresponding form of the vs. curves is in agreement with the observed dispersion of the molecular field .