Development of a Plasticity-oriented Interatomic Potential for CrFeMnNi High Entropy Alloys

Development of an Interatomic Potential for the Simulation of Defects, Plasticity and Phase Transformations in Titanium

New interatomic potentials describing defects, plasticity and high temperature phase transitions for Ti are presented. Fitting the martensitic hcp-bcc phase transformation temperature requires an efficient and accurate method to determine it. We apply a molecular dynamics (MD) method based on determination of the melting temperature of competing solid phases, and Gibbs-Helmholtz integration, and a lattice-switch Monte Carlo method (LSMC): these agree on the hcp-bcc transformation temperatures to within 2 K. We were able to develop embedded atom potentials which give a good fit to either low or…

用新原子间势模拟KTaO$_3$钙钛矿的位错与塑性

Dislocations and plasticity of KTaO$_3$ perovskite modeled with a new interatomic potential

本文提出新的KTaO3原子间势并模拟<110>位错，揭示其分解、核心结构、Peierls势及电荷中性偏好，结合高分辨电镜验证，确认KTaO3延展但比SrTiO3更刚硬。

Artificial neural network interatomic potential for dislocation and fracture properties of Molybdenum

A high dimensional artificial neural network interatomic potential for Mo is developed. To train and validate the potential density functional theory calculations on structures and properties that correlate to fracture, such as elastic constants, surface energies, generalized stacking fault energies, and surface decohesion energies, have been employed. The potential provides total energies with a root mean square error less than 5\;meV per atom both in the training and validation data sets. The potential was applied to investigate screw dislocation core properties as well as to conduct large s…

First principles interatomic potential for tungsten based on Gaussian process regression

An accurate description of atomic interactions, such as that provided by first principles quantum mechanics, is fundamental to realistic prediction of the properties that govern plasticity, fracture or crack propagation in metals. However, the computational complexity associated with modern schemes explicitly based on quantum mechanics limits their applications to systems of a few hundreds of atoms at most. This thesis investigates the application of the Gaussian Approximation Potential (GAP) scheme to atomistic modelling of tungsten - a bcc transition metal which exhibits a brittle-to-ductile…

Atomistic simulations of nanoindentation in single crystalline tungsten: The role of interatomic potentials

Computational modeling is usually applied to aid experimental exploration of advanced materials to better understand the fundamental plasticity mechanisms during mechanical testing. In this work, we perform Molecular dynamics (MD) simulations to emulate experimental room temperature spherical-nanoindentation of crystalline W matrices by different interatomic potentials: EAM, modified EAM, and a recently developed machine learned based tabulated Gaussian approximation potential (tabGAP) for describing the interaction of W-W. Results show similarities between load displacements and stress-strain…

Cu-W体系缺陷与热力学的原子簇展开原子间势

Atomic cluster expansion interatomic potential for defects and thermodynamics of Cu-W system

本文基于原子簇展开方法为Cu-W不混溶体系开发了精确的机器学习原子间势，通过DFT和实验验证了其基本性质与热力学性质，并利用MC-MD模拟揭示了相分离和上坡扩散的原子机制。