Predictive Modelling of the Fundamentals of Failure in Metals

我们缺乏对原子尺度机制的详细了解，这些机制导致金属通过诸如开裂、蠕变、脆化或疲劳等过程失效，这是令人惊讶的，因为这种了解可能产生重大的技术和经济影响。可以实现的例子包括为飞机发动机设计更强、更轻的涡轮机叶片，为汽车工业设计更轻的合金，或为核工业设计更好的辐射屏蔽。迄今为止，进展有限，部分原因是目前这一代金属失效的连续体模型严重依赖于经验方法。这项建议的首要目标是开发新的模型，使连续规模的建模故障过程，特别是裂纹扩展，通过将预先计算的第一原理信息。添加可靠的概率“误差条”，其中包括模型误差、有限数据、认识不确定性和粗粒度的影响，将有助于解决阻碍工业中更广泛采用材料建模的主要障碍之一（参见实现这些长期目标首先需要开发（一）金属“缓慢”失效过程的精确原子尺度模型和（二）严格的模型简化程序，以捕获粗粒化过程中丢失的信息，从而模拟复杂的微观结构。该项目通过开发新的方法来详细解决（i）在足够大的系统中计算具有QM精度的能垒，以捕获应力集中，并应用于技术相关但结构仍然简单的单晶模型系统（镍，铝和钨）中的位错运动和裂纹生长。要求（ii）将通过一个案例研究进行探讨，并在未来的提案中进一步发展。该项目与英国处于世界领先地位的研究领域保持一致：凝聚态物质（电子结构），材料工程（金属和合金）和数值分析。

Our lack of detailed understanding of the atomic scale mechanisms which lead to failure of metals through processes such as cracking, creep, embrittlement or fatigue is surprising, given the significant technological and economic impact that such understanding could generate. Examples of what could be achieved include designing stronger, lighter turbine blades for aeroplane engines, improved lightweight alloys for the automobile industry or improved radiation shields for the nuclear industry.Progress to date has been limited partly because the current generation of continuum models for metal failure rely heavily on empirical methods. The overarching aim of this proposal is to develop new models to enable continuum-scale modelling of failure processes, in particular crack growth, by incorporating pre-computed first-principles information. Adding reliable probabilistic "error bars'' which incorporate the effects of model error, limited data, epistemic uncertainty and coarse-graining would help to address one of the major barriers holding back wider adoption of materials modelling in industry (cf. Innovate UK/KTN special interest group on Uncertainty Quantification and Management for High Value Manufacturing).Realising these long-term aims first requires developing (i) accurate atomic scale models for `slow' failure processes in metals and (ii) a rigorous model reduction procedure to capture information lost during coarse graining, allowing complex microstructures to be modelled. This project addresses (i) in detail by developing new methodology to compute energy barriers with QM accuracy in systems large enough to capture stress concentration, with application to dislocation motion and crack growth in technologically relevant but still structurally simple single crystal model systems (nickel, aluminium and tungsten). Requirement (ii) will be explored via a case study to be further developed in future proposals.The project is aligned with research areas in which the UK is a world leader: condensed matter (electronic structure), materials engineering (metals and alloys) and numerical analysis.