Evolution of tensile damage in porous iron

The evolution of damage in porous iron was studied by monitoring both Youngʹs modulus and density changes during tensile testing. Damage was found to develop in two stages. During the first stage (up to nominal plastic deformations between 0.015 and 0.02), plastic deformation was highly localized at the pore edges, whereas during the second stage bulk deformation took place. Since porosity introduces imperfections in the microstructure with favorable paths for damage accumulation, new relations for the evaluation of damage were developed. These relations were used to predict damage evolution during the second stage. It was shown that the two methodologies of indirect damage evaluation can give a unified description of damage, if the peculiarities of deformational behavior of materials are properly considered.