Uniaxial deformation of open-cell aluminum foam: the role of internal damage

Internal damage accumulation is measured and shown to play a role in the mechanical response of replicated pure Al and Al-12Si open-cell foams. This internal damage is quantified by measuring the reduction in the foam's stiffness with strain. The brittle Si second phase fractures during deformation of Al-12Si foam, resulting in damage accumulation rates an order of magnitude greater than for pure Al foam. Elementary damage mechanics is used to relate the measured rate of damage accumulation to the foam's tensile failure strain. The analysis and experimental results highlight in particular the strong embrittling influence of brittle second phases within the foam, such as Si.