Effect of chemical composition and heat treatment on hydrogen embrittlement susceptibilities of 4340M Martensitic and Bainitic steels

化学成分和热处理对4340M马氏体和贝氏体钢氢脆敏感性的影响

• 批准号: 543696-2019
• 负责人: Song, Jun
• 金额: $ 5.6万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=719884
• 关键词: Effect; chemical; composition; heat; treatment

High strength materials are often used for their high specific strength in limited space. Among those, low alloy steels exhibit a combination of high strength, ease of production and manufacturability, making them an economical and worthwhile choice for many structural components (e.g., landing gear, fasteners and actuators) in aerospace and manufacturing industries. Despite the various beneficial properties offered, one common problem low alloy steel suffers is hydrogen embrittlement (HE), i.e., the material experiences deterioration in mechanical properties and subsequent premature and delayed brittle fracture, in the presence of hydrogen that is often introduced during the plating process. In combating HE, it is necessary to have accurate material-specific knowledge of hydrogen trapping and HE susceptibility so that appropriate measures (e.g., baking to remove hydrogen and determination of in-service loading levels) can be taken. AISI 4340 steel has been the prevailing landing gear material used in aerospace applications. Recently, AISI 300M (4340M) low alloy steel and Bainitic steel were developed as alternative materials due to the improved strength, superior fracture toughness and impact strength. Their mechanical properties can be further tuned by additional thermal/mechanical treatments. However, hydrogen trapping characteristics and HE susceptibility of those materials remain unknown. This project aims to address such knowledge deficit by conducting a detailed study to identify key microstructural metrics responsible for hydrogen trapping and establish threshold curves for 4340M and Bainitic steel. Further, a microstructure-informed numerical model will be developed to enable generic numerical analysis of hydrogen trapping and HE susceptibility for low alloy steel, and atomistic simulations will be performed to gain fundamental understanding of the role of alloy carbides in HE of low alloy steel. Outcomes from this project will provide the industrial partners better and quantitative knowledge of the effect of microstructure on hydrogen trapping and HE susceptibility of low alloy steel, and subsequently help them take informed and reliable decisions in practices towards HE prevention.

高强度材料由于其在有限空间内的高比强度而经常被使用。其中，低合金钢表现出高强度、易于生产和可制造性的组合，使其成为许多结构部件（例如，起落架、紧固件和致动器）。尽管提供了各种有益的性能，但低合金钢遭受的一个常见问题是氢脆（HE），即，在电镀过程中经常引入的氢的存在下，材料经历机械性能的劣化以及随后的过早和延迟的脆性断裂。在对抗HE时，有必要对氢捕获和HE敏感性具有准确的材料特定知识，以便采取适当的措施（例如，烘烤以除去氢和确定使用中的装载水平）。AISI 4340钢一直是航空航天应用中常用的起落架材料。近年来，AISI 300 M（4340 M）低合金钢和贝氏体钢由于其强度提高、上级断裂韧性和冲击强度优异而被开发作为替代材料。它们的机械性能可以通过额外的热/机械处理进一步调整。然而，这些材料的氢捕获特性和HE敏感性仍然未知。 该项目旨在通过进行详细的研究来确定负责氢捕获的关键微观结构指标，并建立4340 M和贝氏体钢的阈值曲线，以解决这种知识不足。 此外，将开发一个微观结构知情的数值模型，使通用的数值分析的氢陷阱和HE敏感性的低合金钢，原子模拟将进行，以获得合金碳化物在低合金钢的HE的作用的基本理解。该项目的成果将为工业合作伙伴提供有关微观结构对低合金钢的氢捕集和HE敏感性的影响的更好和定量的知识，并随后帮助他们在实践中对HE预防做出明智和可靠的决策。