Dislocation nucleation and motion in metals and alloys at high-rate deformation: Molecular dynamic simulation
AY Kuksin and AV Yanilkin, MECHANICS OF SOLIDS, 50, 44-51 (2015).
Molecular dynamic simulation was used to calculate the critical stresses necessary for dislocations to nucleate and move in the dynamic friction mode and determine the coefficients of dislocation phonon friction in metals with point defects and Guinier-Preston (GP) zones (in the Al-Cu alloy) taken into account. The temperature dependencies of the critical stresses required to overcome the GP zones in Al at different speeds of dislocation motion were analyzed to distinguish the thermofluctuation and dynamic (weakly depending on T) contributions to the yield strength at high-rate deformations. It was noted that the dislocation nucleation stresses strongly decrease with increasing temperature in the defect- free case and the stresses of dislocation heterogeneous nucleation on GP clusters remain nearly unchanged.
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