Precipitation behavior of intermetallic NiAl particles in Fe-6 at.%Al-4 at.%Ni analyzed by SANS and 3DAP

Three-dimensional atom probe (3DAP) measurements and in-situ small-angle neutron scattering (SANS) were conducted in order to study the precipitation behavior of an Fe-6 at.%Al-4 at.%Ni alloy. The radius, number density and volume fraction of intermetallic NiAl precipitates were determined by a cluster search algorithm applied on the 3DAP data as well as by the evaluation of scattering curves obtained from SANS. The chemical compositions of the NiAl precipitates, found by 3DAP, and the experimental R-value obtained from SANS, were used to calculate the nuclear scattering contrasts. The introduction of 3DAP results enables an accurate evaluation of magnetic SANS curves by providing information on the magnetic scattering contrast. It is shown that a high amount of Fe is incorporated in the NiAl precipitates which gives rise to a magnetic moment. Finally, the results on the precipitation kinetics gained by 3DAP and SANS were combined and subsequently used to model the hardness behavior of the model alloy.