Void configuration under constrained deformation in ductile matrix materials

SiC particle reinforced Al 2025 aluminum alloy composite is used for tensile tests. The ductile fracture by nucleation, growth and coalescence of micro voids, particle cracking and the interfacial debonding under the different constraint conditions, which are obtained by changing the notch radius, is analyzed. The effect of the local constraint on the respective damage phenomenon is analyzed using the axi-symmetric unit cell FE model by changing the local stress triaxiality and side constraint. The results show that the fracture process of the notched tensile bar is simulated well and the damage phenomena agree qualitatively with the experimental ones. Finally the effect of constraint on the void configuration and coalescence is investigated experimentally using three-dimensional fracture surface observations using the SEM (scanning electron microscope) and three-dimensional imaging analysis method. The constraint effect is analyzed by changing the specimen’s shape. The experimental results show that the void aspect ratio is decreased with increases of SiC particle volume fraction in aluminum alloy. The final void volume fraction at fracture also changes by the specimen shape and the material’s structure.