A 3-dimensional dislocation-density multiple-slip crystalline model was developed for the accurate characterization of the failure mechanisms that could occur at various scales in intermetallics which were subjected to high strain-rates. This model accounted for the generation, trapping, interaction and annihilation of mobile and immobile dislocations at densities which were usually associated with finite-strain, and high strain-rate, plasticity in L12 ordered intermetallics. Coincidence-site lattice and random grain-boundary effects upon intergranular and transgranular failure at triple junctions were investigated. The results indicated that intergranular cracks could nucleate due to dislocation pile-ups along the grain boundaries, and that transgranular failure occurred on slip-planes that intersected the grain boundaries.

Inelastic Three-Dimensional High Strain-Rate Dislocation Density Based Analysis of Grain-Boundary Effects and Failure Modes in Ordered Intermetallics M.A.Zikry, T.Kameda: Mechanics of Materials, 1998, 28[1-4], 93-102