Studies of precipitation using small-angle neutron scattering (SANS)

Some earlier results are summarized which demonstrate the range of applications of SANS in the study of inhomogeneities. The size, number density, chemical composition (Ni₃Al_0.6Ti_0.4) and kinetics of the γ′ precipitates in a Nimonic superalloy have been determined by SANS. The formation and growth of voids on the grain boundaries of a Nimonic superalloy have been followed by in situ SANS. The crystallographically aligned θ′ precipitates in an Al–Cu crystal exhibit anisotropic SANS from which the edge lengths of the θ′ platelets have been determined. Finally, SANS was used to study a very dilute concentration (20 p.p.m.) of the second phase particles in a silicon crystal.