Multiscale simulations of plasticity and fracture: the atomic-scale mechanisms of hydrogen embrittlement in engineering alloys.

塑性和断裂的多尺度模拟：工程合金中氢脆的原子尺度机制。

• 批准号: RGPIN-2014-03760
• 负责人: Miller, Ronald
• 金额: $ 3.21万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=638128
• 关键词: Multiscale; simulations; plasticity; fracture; atomic

Molecular dynamics (MD) and atomistic simulations have the potential to impact areas ranging from nanotechnology, to drug design, to the next generation of advanced materials. However, the predictive capabilities of MD are limited in several ways. The two most significant limitations are the prohibitively small numbers of atoms that can be studied and the limited availability (or sometimes complete lack of availability) of accurate interatomic potentials for many important combinations of atomic species. This research pursues the development of methodologies, algorithms and tools that help to overcome these obstacles. At the same time, we will use these tools to study important scientific questions related to the mechanical failure of materials at the nanoscale. These questions have consequences for the design of materials with enhanced properties, for our understanding of nanostructures, and for the fundamentals of fracture and failure in structural materials.Understanding and predicting fracture is, of course, of fundamental importance to engineering. The more accurate and reliable our understanding of the process, the better equipped we are to confidently design lightweight, long-serving structures that will not fail suddenly and catastrophically. This research focusses on applying atomic scale models to advance our understanding of fundamental aspects of plasticity and fracture in structural engineering metals, specifically addressing the important role that hydrogen plays in making certain important metals more brittle. For example, we will address hydrogen embrittlement effects in aluminum alloys, and the role of hydrides (precipitated hydrogen compounds) in the fracture behaviour of zirconium alloys. The research methodology will use computer simulation techniques that have been developed by the PI's research group and other researchers. For example, we will use multiscale methods that extend the size of the simulation that can be run with atomistic accuracy. This is accomplished through judicious choice of which regions of the problem are treated using a fully atomistic description, allowing us to study hydrogen-aluminum interactions within realistic configurations of atoms around a stressed crack tip. As well, we will employ computational methods to explore atomic configurations and accurately determine the activation energy associated with key processes like dislocation nucleation. Accurate knowledge of such data is of fundamental importance to any larger scale models aiming to predict fracture toughness. Finally, the project will both utilize and build upon the recent openKIM.org project to develop new accurate models to describe the zirconium-hydrogen system. This will allow us to study the complex interactions between cracks and embedded hydrides.

分子动力学（MD）和原子模拟有可能影响从纳米技术到药物设计再到下一代先进材料的各个领域。然而，MD的预测能力在几个方面受到限制。两个最重要的限制是可以研究的原子数量非常少，以及对于许多重要的原子种类组合，精确的原子间势的可用性有限（有时完全缺乏可用性）。这项研究致力于开发有助于克服这些障碍的方法、算法和工具。与此同时，我们将使用这些工具来研究与纳米级材料的机械失效相关的重要科学问题。这些问题对于设计具有增强性能的材料、理解纳米结构以及结构材料断裂和失效的基本原理都有重要意义。当然，理解和预测断裂对工程具有根本的重要性。我们对这一过程的理解越准确、越可靠，我们就越有信心设计出轻质、长期使用的结构，这些结构不会突然发生灾难性的故障。这项研究的重点是应用原子尺度模型，以促进我们对结构工程金属塑性和断裂基本方面的理解，特别是解决氢在使某些重要金属更脆方面所起的重要作用。例如，我们将讨论铝合金中的氢脆效应，以及锆合金断裂行为中沉淀氢化合物的作用。研究方法将使用PI研究小组和其他研究人员开发的计算机模拟技术。例如，我们将使用多尺度方法来扩展可以以原子精度运行的模拟的大小。这是通过明智的选择，该地区的问题进行治疗，使用一个完全原子的描述，使我们能够研究氢铝相互作用的原子周围的应力裂纹尖端的现实配置。此外，我们将采用计算方法来探索原子构型，并准确地确定与位错成核等关键过程相关的活化能。这些数据的准确知识是至关重要的任何更大规模的模型，旨在预测断裂韧性。最后，该项目将利用并建立在最近的openKIM.org项目的基础上，开发新的精确模型来描述锆-氢系统。这将使我们能够研究裂纹和嵌入的裂纹之间复杂的相互作用。