Strain-induced morphologies during homogeneous phase separation in alloys

When precipitates grow with a lattice misfit inside a matrix having cubic crystal symmetry, a transition may occur from an isotropic arrangement of the precipitates to an alignment along the cubic directions of the crystal. Furthermore, if a uniaxial external strain is applied, an additional transition towards tetragonal symmetry can occur by fusion of the precipitates into large plates perpendicular (or long rods parallel) to the direction of applied strain (“rafting”). Recent experiments on Ni-Al-Mo alloys as well as computer simulations relating to these two transitions are reviewed.