Clustering in Cu-Ni alloys: A diffuse neutron-scattering study

Clustering in Cu-Ni was measured from the diffuse scattering of thermal neutrons, using the special isotopes ${}_{}{}^{62}{}_{}{}^{}\mathrm{Ni}$ and ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$ for optimizing scattering conditions. Both the temperature and the composition dependence of clustering have been studied systematically. Alloys with compositions ranging from 20- to 80- at.% Ni were investigated in equilibrium for temperatures between 400 and 700°C. The cluster parameters show a strong asymmetry in their composition dependence. This asymmetry appears to be temperature dependent. The results show that many-particle interactions play an important role in determining the amount of clustering in Cu-Ni. The location of the miscibility gap is calculated.