Damage controlled by brittle particles crush in AA7075-T6 beneath spherical indenter

The distribution of damage controlled by brittle particles crush in AA7075-T6 beneath spherical indenter was obtained experimentally and predicted analytically. Micro hardness tests were conducted on the vertical sections across the indentation impression and by comparing it with the estimated ideal micro hardness, the damage beneath spherical indenter can be quantified. In the present study, for a spherical indenter with 794 μm radius and a 117 μm penetration, maximum damage is 0.29, locating in the middle of the contact arc. The damage along path 1, which is right below the indentation impression, has generally smaller damage and the path 3, which is below the middle of the contact arc, has more extensive damage. Through a model which can describe the damage controlled by second phase particles crush, a modified expanding cavity model (ECM) coupling with the Ramberg-Osgood stress-strain relation was applied to predict the distribution of damage in spherical indentation deformation. By comparing with the experimental results, it proved that the method could give a prediction with reasonable accuracy.