Molecular Dynamics Simulation of Crack Propagation in Nanoscale Polycrystal Nickel Based on Different Strain Rates

Abstract

Based on the strain rates of 2 × 10 8 s −1 and 2 × 10 10 s −1 , molecular dynamics simulation was conducted so as to study mechanisms of crack propagation in nanoscale polycrystal nickel. The strain rate has an important effect on the mechanism of crack propagation in nanoscale polycrystal nickel. In the case of a higher strain rate, local non-3D-crystalline atoms are induced and Lomer-Cottrell locks are formed, which plays a critical role in crack initiation and propagation. Orientation difference between adjacent grains leads to the slipping of dislocations along the different directions, which results in the initiation of a void near the triple junction of grain boundaries and further contributes to accelerating the crack propagation.

Mechanical behaviour and microstructural evolution of Ni-based single crystal alloys under shock loading

“…Molecular dynamics simulations are widely used for these applications and allow easy modelling and accurate calculations that are easy to intuitively carry out. [15][16][17][18] This study uses molecular dynamics simulations. The embedded atom method (EAM) is used to simulate the microstructure evolution of Nibased single-crystal alloys.…”

First-Principles Approaches to Metals, Alloys, and Metallic Compounds

“…Eventually, they develop an approximative scheme to estimate grain-boundary energies for varying C and H contents, and they consider the dependence of hydride formation on the grain-boundary stiffness. When it comes to time evolution and dynamical phenomena, the paper by Zhang and Jiang [6] deals with molecular-dynamics simulations of crack propagation in nanoscale polycrystalline nickel. The strain rate has an important effect on the mechanism of crack propagation, and for higher strain rates local, non-3D-crystalline atoms show up, and Lomer-Cottrell locks are formed.…”

The Microstructural Evolution of Nickel Single Crystal under Cyclic Deformation and Hyper-Gravity Conditions: A Molecular Dynamics Study

“…Yang et al [18] revealed that the fatigue cracks in the Ni-Fe alloy caused by the coalescence of nanovoids are before the main crack tips. For polycrystal, Zhang et al [19] studied the strain rate effect on the crack propagation mechanisms of nickel. Zhou et al [20] extracted the da/dN metrics from the fatigue crack growth in polycrystal coherent twins.…”