High strain-rate modeling of the interfacial effects of dispersed particles in high strength aluminum alloys

The interfacial effects of dispersed particles on the dynamic deformation of high strength aluminum alloys have been investigated using an eigenstrain-based formulation coupled with dislocation-density based crystalline plasticity and a microstructurally based finite element framework. This accounts for the unrelaxed plastic strains associated with the interfacial behavior of dispersed particles, such as Orowan looping. Particle spacing had a significant effect on the distribution of plastic shear slip, with localization occurring between the particles for smaller particle spacing. The eigenstress field associated with larger particles led to longer-range interaction of pressure fields, which can promote void coalescence for nucleated voids at the particle-matrix interface. Grain orientation also had a significant effect on the behavior associated with the particles, with plastic shear slip localizing at the particle-matrix interfaces for low angle grain-boundary (GB) misorientations, and at GBs and GB junctions for high angle GB misorientations.