Void Shape Effects on Void Growth and Slip Systems Activity in Single Crystals

Cast void shape effects on void growth and slip system activity in single crystals were studied using crystal plasticity under various orientations of the crystalline lattice. A 3D unit cell with ellipsoidal void was set up using three-dimensional 12 potentially active slip systems; the spherical shape of void which is a special case of ellipsoid was also included. The numerical results show that the initial texture orientation, the ellipsoidal coordinate, the load coordinate system and the shape of void have a competitive effect on the evolution of voids. For triaxial tension conditions, the void fraction increase under the applied load is strongly dependent on the shape of void and the crystallographic orientation with respect to the load axis, as well as the activities on all the slip systems. When the symmetry of the unit cell is broken, the void experiences a rotation in spite of the load applied along <001> and <011> orientations with symmetry of the slip systems. An interesting feature is that, even in the case of anisotropic crystalline matrix materials, the overall effect of plastic anisotropy on damage evolution is diminished during non-spherical void growth.