Fast Slip Velocity in a High-Entropy Alloy

Due to fluctuations in nearest-neighbor distances and chemistry within the unit cell, high-entropy alloys are believed to have a much higher resistance to dislocation motion than pure crystals. Here, we investigate the coarse-grained dynamics of a number of dislocations being active during a slip event. We found that the time-resolved dynamics of slip is practically identical in AuaOE (c) 001 > and an Al(0.3)CoCrFeNiaOE (c) 001 > high-entropy alloy, but much faster than in NbaOE (c) 001 >. Differences between the FCC-crystals are seen in the spatiotemporal velocity profile, with faster acceleration and slower velocity relaxation in the high-entropy alloy. Assessing distributions that characterize the intermittently evolving plastic flow reveals material-dependent scaling exponents for size, duration, and velocity-size distributions. The results are discussed in view of the underlying dislocation mobility.