Effect of uniaxial stress on coarsening of precipitate clusters

The influence of moderate applied uniaxial stresses (σ_app/C ₄₄ ≈ 10⁻³) on the coarsening behavior of misfitting coherent precipitates in binary alloys has been studied. Three-dimensional (3-D) computer simulations of the coarsening have been performed for elastically homogeneous systems with tetragonal misfit strain and elastically heterogeneous systems with dilatational misfit strain. Precipitate shapes are restricted to spheres. Results depend on the sign of the misfit strain, the sign of the applied field, and the character of the elastic heterogeneity: precipitates softer than the matrix phase with positive (negative) misfit strain align along the direction of the applied stress for compressive (tensile) fields and arrange in planes perpendicular to it for tensile (compressive) fields. Precipitates harder than the matrix behave in the opposite way. This article is based on representation made during TMS/ASM Materials Week in the symposium entitled “ldAtomistic Mechanisms of Nucleation and Growth in Solids,” organized in honor of H.I. Aaronson’s 70th Anniversary and given October 3–5, 1994, in Rosemont, Illinois.