PERCOLATION AND DAMAGE BEHAVIOR IN MATERIALS WITH LIQUID GRAIN-BOUNDARIES

Percolation of the liquid phase and the damage behaviour in an aluminium alloy with liquid grain boundaries were characterized in experiments performed in tension and compression. The effects of the local stresses (due to grain-boundary sliding and macroscopic stresses) on the percolation of the liquid phase and on cavity development are discussed. It was found that cavities always appear and grow in the intergranular liquid films. It is shown that the presence of liquid films facilitates cavity formation and specimen rupture, for test conditions inducing local stresses higher than a critical stress. In contrast, for local stresses below the critical stress for hole formation, the liquid phase appeared to allow easy accommodation of the deformation without any damage.