EFFECT OF UNIAXIAL-STRESS ON COARSENING OF PRECIPITATE CLUSTERS

The influence of moderate applied uniaxial stresses (sigma(app)/C-44 a pproximate to 10(-3)) on the coarsening behavior of misfitting coheren t precipitates in binary alloys has been studied. Three-dimensional (3 -D) computer simulations of the coarsening have been performed for ela stically homogeneous systems with tetragonal misfit strain and elastic ally heterogeneous systems with dilatational misfit strain. Precipitat e 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 ap plied stress for compressive (tensile) fields and arrange in planes pe rpendicular to it for tensile (compressive) fields. Precipitates harde r than the matrix behave in the opposite way.