This picture shows profiles of blunted cracks, just after reaching the interface in the dynamic cleavage test, in (a) 2D (G/Glc = 1.27) and (b) 3D FCC (G/Glc = 1.39). For both tests,the second material corresponds to the most ductile potential; atoms in the second material are colored according to their centrosymmetry, which reveals dislocations/stacking faults.
Ref: Crack Tip Blunting and Cleavage Under Dynamic Conditions by Varun Rajan et al.