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、药物设计到下一代先进材料等领域。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极少，以及许多重要原子种类组合的准确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。同时，我们将利用这些工具来研究与纳米尺度材料机械失效相关的重要科学问题。这些问题对于性能增强材料的设计、我们对纳米结构的理解以及结构材料断裂和失效的基本原理都有影响。当然，理解和预测断裂对于工程至关重要。我们对这一过程的理解越准确和可靠，我们就越有能力自信地设计出轻质、长期使用的结构，这些结构不会突然发生灾难性的失效。这项研究的重点是应用原子尺度模型来增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变得更脆方面所发挥的重要作用。例如，我们将讨论铝合金中的氢脆效应，以及氢化物（沉淀的氢化合物）在锆合金断裂行为中的作用。研究方法将使用由 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规模。这是通过明智地选择使用完全原子描述来处理问题的哪些区域来实现的，使我们能够研究受应力裂纹尖端周围原子的真实构型内的氢-铝相互作用。此外，我们将采用计算方法来探索原子构型并准确确定与位错成核等关键过程相关的活化能。准确了解此类数据对于任何旨在预测断裂韧性的大型模型至关重要。最后，该项目将利用并以最近的 openKIM.org 项目为基础，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氢化物之间的复杂相互作用。