Molecular Dynamics Simulation of the Interaction between Dislocations and Iron–Vanadium Precipitates in Alpha Iron: Effect of Chemical Composition

Abstract

In this study, molecular dynamics simulations were employed to study the interaction between dislocations with Fe-V precipitate with different vanadium concentrations. Increasing the vanadium concentration in the precipitate results in a strong interaction between the dislocations and the precipitate, and the dislocation line bows out more as a result of increasing the energy of the dislocation line, and the critical stress needed for depinning the dislocations increases. However, at a low vanadium concentration (1:3 atomic ratio) the dislocations cut through the precipitate without changing the speed. An increasing vanadium concentration not only affects the dislocation shape and movement speed, but also affects the configuration of the junction between the a/2[111] and a/2[100] dislocations, and the void formation after the cutting process. The formation of strong junctions and a high number of voids locks the a/2[111] dislocation motion, and increases the strength of the alloy. The results of the radial distribution function before and after the cutting process show that the structure of the precipitate changes from crystalline to amorphous, and the degree of amorphization decreases with an increasing vanadium concentration.

Fatigue and Fracture Behaviors of Short Carbon Fiber Reinforced Squeeze Cast AZ91 at 20 °C and 250 °C

“…relationship between the serrated flow and the dynamic strain aging was induced by the factor of excess magnesium [52,53]. This serrated flow could also result from the repeated dynamic effects of pinning and unpinning [54,55]. It is also suggested that the serrations are formed due to the competition between the precipitate displacement caused by the dislocations and the dynamic strain aging [50,55].…”

Hot Deformation Behavior and Mechanisms of SiC Particle Reinforced Al-Zn-Mg-Cu Alloy Matrix Composites

“…Apart from the stress state, the internal failure of components is also influenced by softening processes like recovery and recrystallization [28]. However, the previous research on the hot deformation behavior of composites are studied mostly through theories more suitable for single-phase homogeneous materials, without fully investigating the effect of reinforcement particles on the microstructure evolution of composites [29,30]. In addition, considering that the deforming components are manipulated by complicated states of stress, temperature and strain rate, a comprehensive study about the effect of deformation processing conditions on the deformation behavior and failure mechanism of composites is necessary.…”