Fatigue Deformation of Polycrystalline Cu Using Molecular Dynamics Simulations

Abstract

Molecular dynamics (MD) simulations have been performed to investigate the fatigue deformation behaviour of polycrystalline Cu with grain size of 5.4 nm. The samples were prepared using Voronoi algorithm with random grain orientations. Fatigue simulations were carried out by employing fully reversed, total strain controlled cyclic loading at strain amplitude of ±4% for 10 cycles. The MD simulation results indicated that the deformation behaviour under cyclic loading is dominated by the slip of partial dislocations enclosing the stacking faults. At higher number of cycles, the grain boundary migration leading to coarsening of larger grains at the expense of the smaller grains has been observed. The cyclic stress-strain behaviour, the deformation mechanisms and the variation of dislocation density as a function of cyclic deformation have been discussed.

Twin boundary reversibility characteristics in α-Fe

“…This twin boundary (Σ3(112)) in α-Fe does not carry the perfect mirror symmetry [32]. Periodic boundary conditions were applied in the Y [-101] direction, while the other two directions (X [121], Z [1][2][3][4][5][6][7][8][9][10][11]) were free to mimic the free surfaces. The simulation box has been divided into three regions, viz, two rigid regions at the top and the bottom portions along the X-axis, and the remaining middle portion as the active deformation region.…”

“…Yang Yang et al [2] reported good stress-strain recoverability in pre-twinned α-Fe under torsion. Sainath et al [10] reported coherent twin formation from incoherent twins and their stabilization in further cyclic loading in polycrystalline Cu. All these results underlined the crucial role of GBs in plastic reversibility.…”

Atomistic simulation of rolling contact fatigue behavior of a face‐centered cubic material (nickel)

“…There have also been several fatigue studies using MD techniques to evaluate various dynamic parameters and structural stability. The deformation behavior of polycrystalline Cu and nickel nanowires is studied because of cyclical loading on the specimen 40,41 , the fatigue cracks growth MD model is being developed to simulate the crack growth phenomenon in the single crystal and polycrystalline material, [42][43][44] and compression-compression fatigue simulations have been modeled on metallic glass nanowires to evaluate the deformation behavior 45 . Although there have been several MD investigations on specimens under applied rolling and fatigue deformation processes, there are very few MD simulation studies using the RCF process.…”

Fatigue-driven acceleration of abnormal grain growth in nanocrystalline wires

“…Cyclic hardening was also observed. Sainath, Rohith and Choudhary [32] performed cyclic loading of polycrystalline Cu with amplitudes of 4% for 10 cycles. These simulations demonstrated partial dislocation slip, as well as grain boundary motion leading to grain coarsening.…”