Predictive Modelling of the Fundamentals of Failure in Metals

我们缺乏对通过破裂、蠕变、脆化或疲劳等过程导致金属失效的原子尺度机制的详细了解，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坚固、更轻的涡轮叶片，为汽车工业设计更轻的合金，或者为核工业设计更好的辐射屏蔽。到目前为止，进展有限，部分原因是当代金属失效的连续介质模型严重依赖经验方法。这一建议的总体目标是开发新的模型，通过纳入预先计算的第一原理信息，能够对失效过程，特别是裂纹扩展进行连续尺度模拟。增加包含模型误差、有限数据、认知不确定性和粗粒化影响的可靠的概率“误差条”将有助于解决阻碍在工业中更广泛地采用材料模型的主要障碍之一(参见。创新英国/KTN关于高价值制造的不确定性量化和管理的特别兴趣小组).要实现这些长期目标，首先需要开发(I)准确的原子尺度金属失效过程模型，(Ii)严格的模型简化程序，以捕捉粗粒化过程中丢失的信息，从而能够对复杂的微结构进行建模。该项目详细介绍了(I)开发新的方法，在足以捕捉应力集中的大小的系统中以QM精度计算能垒，并应用于技术上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扩展。需求(Ii)将通过一个案例研究进行探索，并在未来的提案中进一步发展。该项目与英国在以下领域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.