Next Generation Electro-Chemo-Mechanical Models for Hydrogen Embrittlement (NEXTGEM)

氢是无处不在的，有两个面孔。一方面，它是解决我们能源危机最有希望的办法的核心。氢同位素为核聚变反应提供燃料，这是最有效的潜在可用能源过程。此外，氢被广泛认为是未来的能源载体和最通用的储能手段。氢气可以通过电解从风能或太阳能等可再生能源中产生，并储存起来用作燃料或化学工业的原材料。另一方面，众所周知，氢气会导致金属材料和结构的灾难性故障，阻碍了这些机会。金属在暴露于含氢环境中时会变脆，抗断裂性降低高达90%。这种所谓的氢脆现象不仅危及氢作为全球能源危机潜在解决方案的作用，而且还构成了对当前能源基础设施完整性的最大威胁之一。该问题在腐蚀性环境中特别严重，例如海上工业所经历的环境，因为阴极保护等腐蚀性缓解策略加剧了氢的产生。此外，由于现代高强度钢的更高的敏感性，氢脆变得越来越臭名昭著。几十年的冶金研究已经导致了高强度和超高强度金属的发展。这些现代合金在降低重量、材料使用和成本方面开辟了新的视野，同时提高了性能和安全性（抗疲劳性）。例如，超高强度钢对于通过减轻车辆重量来实现二氧化碳排放目标至关重要。然而，对氢脆的敏感性随着材料强度的增加而增加，并且这些新的高性能材料的增加使得氢辅助断裂在各种各样的行业和应用中变得司空见惯，在其他良性环境中，从Leadenhall塔的螺栓开裂到地下系统中的轨道故障。迫切需要了解这种氢致退化背后的多种物理机制，并开发能够预测故障随环境变化的模型，加载条件和材料特性。EPSRC新研究者奖旨在开发新一代模型，该模型可以通过解决电化学-扩散界面和脱落光到表面行为和捕获的关键不确定性。对于给定的大体积环境，氢进入的准确估计是阻碍当前化学力学模型在工程评估中应用的主要瓶颈。诸如裂缝、凹坑或其他缺陷的闭塞区域表现出与本体环境非常不同的化学性质，并且除了受控的实验室实验之外，局部测量是不可行的。NEXTGEM将力学与电化学相结合，结合实验，多物理建模和贝叶斯推理，以解决阻碍氢脆模型适用性的科学挑战。新一代氢脆电化学力学模型将用于安全使用高强度合金，优化材料选择和检测计划，并防止灾难性故障。该项目涉及世界知名的学术合作者，他们的专业知识与PI和海上能源领域的领先公司互补，运营着世界上最古老的大型风电场（Horns Rev 1）。开发的模型的适用性将通过对关键组件的持续监测来证明，这是一项概念验证研究，可能对运输，国防，建筑和能源部门产生更广泛的影响。

Hydrogen is ubiquitous and has two faces. On the one hand, it is at the core of the most promising solutions to our energy crisis. Hydrogen isotopes fuel the nuclear fusion reaction, the most efficient potentially useable energy process. Moreover, hydrogen is widely seen as energy carrier of the future and the most versatile means of energy storage. It can be produced via electrolysis from renewable sources, such as wind or solar power, and stored to be used as a fuel or as a raw material in the chemical industry.On the other hand, hydrogen is widely known to cause catastrophic failures in metallic materials and structures, hampering these opportunities. Metals become brittle when exposed to hydrogen-containing environments, with the fracture resistance decreasing by up to 90%. This so-called hydrogen embrittlement phenomenon not only jeopardises the role of hydrogen as a potential solution to the global energy crisis but also constitutes one of the biggest threats to the integrity of the current energy infrastructure. The problem is particularly severe in aggressive environments, such as those experienced by the offshore industry, as corrosive mitigation strategies like cathodic protection exacerbate the production of hydrogen. Moreover, hydrogen embrittlement is becoming increasingly notorious due to the higher susceptibility of modern, high-strength steels. Decades of metallurgical research have led to the development of metals with high and ultra-high strengths. These modern alloys open new horizons in reducing weight, material use and costs while increasing performance and safety (fatigue resistance). For example, ultra-high strength steels are essential in meeting targets on CO2 emissions through vehicle weight reduction. However, the susceptibility to hydrogen embrittlement increases with material strength and the increasing uptake of these new high-performance materials has made hydrogen assisted fractures commonplace across a wide variety of sectors and applications in otherwise benign environments, from bolt cracking at the Leadenhall tower to rail failures in underground systems. There is an urgent need to understand the multiple physical mechanisms behind this hydrogen-induced degradation and develop models that can predict failures as a function of the environment, the loading conditions and the material properties.This EPSRC New Investigator Award aims at developing a new generation of models that can predict local hydrogen uptake and subsequent cracking by resolving the electrochemistry-diffusion interface and shedding light into critical uncertainties in surface behaviour and trapping. An accurate estimation of hydrogen ingress for a given bulk environment is the main bottleneck preventing the application of current chemo-mechanics models in engineering assessment. Occluded areas such as cracks, pits or other defects exhibit very different chemistry to the bulk environment, and local measurements are unfeasible apart from controlled laboratory experiments. NEXTGEM will merge mechanics with electrochemistry, combining experiments, multi-physics modelling and Bayesian inference to resolve the scientific challenges holding back the applicability of hydrogen embrittlement models. This new generation of electro-chemo-mechanics models for hydrogen embrittlement will be used to enable a safe use of high strength alloys, optimise material selection and inspection planning, and prevent catastrophic failures.The project involves world-renowned academic collaborators with expertise complementary to that of the PI and leading firms in the offshore energy sector, operating the oldest large-scale wind farm in the world (Horns Rev 1). The applicability of the models developed will be demonstrated by continuous monitoring of critical components, in a piece of proof-of-concept research that can have wider implications across the transport, defence, construction and energy sectors.