Comparing Hydrogen Transport and Trapping Mechanisms: Controlling Embrittlement as a Function of Charging Method in Steels and Nickel Alloys

许多当前和下一代能源系统都依赖于气态氢的生产、运输、储存和使用，通常是在高压下。这种系统的安全性、耐用性、性能和经济运行都受到挑战，因为氢会促进高性能材料的各种降解模式。这种降解通常表现为破坏金属和聚合物结构完整性的开裂；一种因降解的时间和操作周期（如应力、氢压力和温度）依赖性而变得复杂的行为。例如，在典型的压力容器或管道环境条件下，同时应力和氢气暴露会导致现代金属系统以十分之一的断裂韧性开裂。这种氢引起的降解现象一般被归类为氢脆。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没有被忽视。这是一个广泛的跨学科问题，涉及到冶金学、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，但管理复杂工程结构暴露在苛刻的环境和机械载荷条件下的人员面临着重大挑战。这里的挑战是将氢损伤机制的争论转变为材料开裂性能的定量预测模型。超越这些挑战的是一个不可避免的事实，即氢损伤问题非常复杂，需要理解在原子尺度上运行的时间周期相关过程，以影响宏观尺度上的行为。在这项研究中，我们将尝试描述氢的溶解度、传输和俘获，这些因素决定了一系列钢基和镍基合金的脆性，这些脆性与氢充电技术（即气体充电与电化学充电）的开裂有关。最初的实验将包括氢渗透研究和热解吸分析，以研究上述合金体系的氢扩散和陷阱特性。进一步的实验工作可能包括断裂力学/断裂韧性测试以及分析电子显微镜。本研究项目由Element Materials Technology提供部分资金，该公司也将提供共同监督。Element Materials Technology是一家为工业提供测试、检验和认证服务的全球供应商，拥有200多个实验室，对金属、复合材料、聚合物、弹性体和树脂进行破坏性和非破坏性测试，以确定它们的潜在特性、性能、强度、耐久性和耐腐蚀性。候选人还将使用位于曼彻斯特大学亨利·罗伊斯先进材料研究与创新研究所的最先进的测试设备。

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.In this study we will attempt to characterise the hydrogen solubility, transport and trapping which govern embrittlement associated with cracking of a range of Steel and Nickel-based alloys as a function of hydrogen charging technique (i.e., gaseous charging vs electrochemical charging). Initial experiments will include hydrogen permeation studies and thermal desorption analysis for hydrogen diffusion and trap character of the above-mentioned alloy systems. Further experimental work could include fracture mechanics / fracture toughness testing as well as analytical electron microscopy. This research project is funded in part by Element Materials Technology who will also provide co-supervision. Element Materials Technology is a global provider of testing, inspection and certification services to industry, with over 200 laboratories conducting destructive testing and non-destructive testing of metals, composites, polymers, elastomers, and resins to determine their potential properties, performance, strength, durability, and resistance to corrosion. The candidate will also make use of the state-of-the-art testing facilities located within the Henry Royce Institute for Advanced Materials Research and Innovation at the University of Manchester.