Hydrogen Transport and Trapping Mechanisms Controlling Embrittlement of Nickel Alloys in Low Carbon Energy Systems

许多当前和下一代能源系统依赖于气态氢的生产、运输、储存和使用，通常是在高压下。由于氢在其他高性能材料中促进了各种降解模式的现实，这类系统的安全性、耐用性、性能和经济运行受到了挑战。这种降解通常表现为破坏金属和聚合物的结构完整性的破裂；这种行为因降解的时间和运行周期(例如，应力、氢气压力和温度)而变得复杂。例如，在典型的压力容器或管道环境条件下，同时施加应力和暴露氢可以在十分之一的断裂韧性下促进现代金属系统的开裂。这种氢致降解现象通常被归类为氢脆。在过去的100年里，科学界进行了大量的工作，氢损伤现象的广度和重要性并不是没有引起注意。这一问题涉及广泛的跨学科，这些工作涉及冶金、化学、固体力学和断裂力学、表面科学、分子和原子氢物理、无损检测、材料表征和机械性能测试。尽管这是一项重要的工作，但管理暴露在苛刻环境和机械载荷条件下的复杂工程结构的任务仍然面临重大挑战。这里的挑战是将关于氢损伤机制的辩论转变为对材料开裂性能的定量预测模型的关注。突出这些挑战的是一个不可避免的事实，即氢损害问题极其复杂，需要了解在原子尺度上运行的依赖于时间周期的过程，以影响在宏观尺度上表现出的行为。

Many current and next generation energy systems are reliant on the production, transportation, storage and use of gaseous hydrogen, often at high pressure. The safety, durability, performance, and economic operation of such systems are challenged due to the reality that hydrogen promotes a variety of degradation modes in otherwise high performance materials. Such degradation is often manifested as cracking which compromises the structural integrity of metals and polymers; a behaviour complicated by time and operating cycle (e.g., stress, hydrogen pressure, and temperature) dependencies of degradation. As an example, concurrent stressing and hydrogen exposure at typical pressure vessel or pipeline environmental conditions can promote cracking in modern metallic systems at one-tenth the fracture toughness. Such hydrogen-induced degradation phenomena are generally categorised as hydrogen embrittlement. The breadth and importance of hydrogen damage phenomena have not gone unnoticed in the scientific community with an immense amount of work conducted over the past 100 years. The problem is broadly interdisciplinary and such work has involved metallurgy, chemistry, solid mechanics and fracture mechanics, surface science, molecular and atomic hydrogen physics, non-destructive inspection, materials characterisation, and mechanical-properties testing. This important work notwithstanding, major challenges face those tasked with managing complex engineering structures exposed to demanding environment and mechanical loading conditions. The challenge here is to transform debate on mechanisms of hydrogen damage into a focus on quantitative, predictive models of material cracking properties. Overarching these challenges is the inescapable fact that hydrogen damage problems are immensely complex, requiring understanding of time-cycle dependent processes operating at the atomic scale to impact behaviour manifest at the macroscopic scale.