PERCOLATION AND DAMAGE BEHAVIOR IN MATERIALS WITH LIQUID GRAIN-BOUNDARIES

Percolation of the liquid phase and the damage behaviour in an alumini um alloy with liquid grain boundaries were characterized in experiment s performed in tension and compression. The effects of the local stres ses (due to grain-boundary sliding and macroscopic stresses) on the pe rcolation of the liquid phase and on cavity development are discussed. It was found that cavities always appear and grow in the intergranula r liquid films. It is shown that the presence of liquid films facilita tes cavity formation and specimen rupture, for test conditions inducin g local stresses higher than a critical stress. In contrast, for local stresses below the critical stress for hole formation, the liquid pha se appeared to allow easy accommodation of the deformation without any damage.