Damage studies in heterogeneous aluminium alloys using X-ray tomography

The role of damage on the mechanical response of a heterogeneous material was investigated through X-ray tomography combined with in situ tensile deformation. This technique enables one to follow the same population of damage-nucleating particles throughout a tensile test. The results indicate that heterogeneity in the spatial distribution of particles does influence the damage process. In particular, particles that are in clusters tend to nucleate damage at lower strain than isolated particles. Nucleation is also enhanced for larger particles and those with higher aspect ratios. Increasing the number of neighbours around a non-isolated particle has no additional influence on the evolution of damage. A model accounting for the multiple cracking of the second phase particles has been developed and incorporated into a self-consistent effective medium analysis model that includes the final stage of damage linkage between cracked particles. The results suggest that while multiple cracking of particles during deformation does accelerate the loss of work hardening with flow, the linkage of damage is the dominant feature which controls the final ductility.