A Comparative Study of Dislocation Dynamics in Ductile and Brittle Crystalline Materials

Dislocation dynamics plays a pivotal role in material failure. Various factors, including impurities, micro-cracks, and voids significantly influence dislocation behavior, leading to failure. Discrete Dislocation Dynamics (DDD) simulations serve as a tool for observing and understanding dislocation interactions at the meso-level. We conducted Two-Dimensional DDD simulations on two distinct crystals, Aluminum and Tungsten, subject to three loading conditions and dislocation densities. Key parameters extracted from the simulation, e.g., collective velocity, plastic strain, shifted position and dislocation count at their metastable configuration showed new insights about the nature of dislocations. Our observations indicate that dislocations in W exhibit a higher average velocity compared to those in Al. Interestingly, even though dislocations in W move at higher velocities, they result in lower plastic strain and fewer dislocations compared to Al with heavy-tail distributions.