Calculation of diffuse scattering near Bragg reflections from coherent precipitates

Numerical calculations of the diffuse scattering near Bragg reflections from coherent solute precipitates in a dilute alloy have been made. Results are presented for spherical precipitates in an elastically isotropic continous medium where the calculations have been reduced to a one-dimensional numerical integral. The scattering is separated into direct scattering from the precipitates, the Huang scattering from the lattice distortions, and the higher-order distortion scattering; calculations are presented for 50 Å radius precipitates with an internal strain of – 1.5%, and the sensitivity of the scattering to changes of the size and the internal strain of the precipitates is demonstrated. The possibility of using such scattering for the determination of the concentration, size distribution, and internal strain of solute precipitates is discussed.