A multiscale approach to understand the role of dislocation motion on carbon mobility and the breakup of carbides in martensitic bearing steels.

一种多尺度方法，用于了解位错运动对马氏体轴承钢中碳迁移率和碳化物分解的作用。

• 批准号: 2444313
• 金额: --
• 依托单位: King's College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2444313
• 关键词: multiscale; approach; understand; role; dislocation

Plasticity in metals is mainly due to dislocation motion. The presence of carbon in steels hinders dislocation motion, leading to a stronger material and this strengthening effect depends on the carbon staying where it is. The decay of martensite under rolling contact fatigue (RCF) is thought to be due to carbon migration - it is the goal of this project to understand the role that dislocation motion plays in the redistribution of carbon under RCF.Results from atomistic simulations such as carbon dislocation binding energies will be used in the next stage of a multiscale approach featuring kinetic Monte Carlo (kMC) simulations of dislocations. From these simulations dislocation mobility rules can be extracted; i.e. functions that relate dislocation velocity to applied stress, temperature and solute concentration. The kMC simulations will also incorporate solute diffusion to ascertain how carbon moves with dislocations in different stress, temperature and concentration regimes. The results of the kMC simulations can be used in a more course-grained approach called discrete dislocation dynamics (DDD) where multiple dislocations and their interactions are simulated. From this approach it is possible to calculate the stress produced in a crystal under a variety of straining conditions. However, it may not be necessary to use DDD if the kMC code developed in this project is successful in simulating multiple dislocations.

金属中的可塑性主要是由于脱位运动。钢中的碳的存在阻碍了脱位运动，从而导致材料更强，这种加强作用取决于碳的留在原地。在滚动接触疲劳（RCF）下，马氏体的衰减被认为是由于碳迁移而引起的 - 该项目的目标是了解在RCF下，碳含量模拟的碳含量重新分布在碳脱位能量（如碳脱位能量）下的作用，将在多issecale Mornct的下一阶段使用（KM）使用（KM）。从这些模拟中，可以提取错位流动性规则；即，将脱位速度与施加的应力，温度和溶质浓度相关的功能。 KMC模拟还将结合溶质扩散，以确定碳在不同的压力，温度和浓度方向上如何通过位错移动。 KMC仿真的结果可用于更循环的方法，称为离散脱位动力学（DDD），其中多个脱位及其相互作用被模拟。通过这种方法，可以计算在各种紧张条件下晶体中产生的应力。但是，如果该项目中开发的KMC代码成功地模拟多个位错，则可能不需要使用DDD。