Concurrent atomistic–continuum simulations of dislocation–void interactions in fcc crystals

• Dislocation–voids interactions are simulated by the CAC method.
• Epinning mechanisms as the void spacings in submicrons are discovered.
• 5 nm voids can even act as weak barriers to dislocations under dynamic conditions.

Dislocation interactions with distributed condensed vacancy clusters in fcc metals were simulated via a concurrent atomistic–continuum method. Due to void strengthening, the dislocation lines are found to bow as a result of pinning on the original glide plane and undergo depinning through drawing out screw dipoles and forming prismatic loops on the secondary slip plane. We discovered an inertia-induced transition between Hirsch looping and void shearing mechanisms as the void spacing ranges from the scale of nm to hundreds of nm. Contrary to prior understanding, simulations suggest that large voids (∼5 nm in diameter) can behave as weak barriers to dislocation motions under high strain-rate dynamic conditions.