NSF-BSF:Influence of cohesion enhancing elements, impurities and hydrogen/deuterium at grain boundaries and heterophase interfaces on embrittlement of additive-manufactured steels

NSF-BSF：晶界和异相界面处的内聚增强元素、杂质和氢/氘对增材制造钢脆化的影响

• 批准号: 2105362
• 负责人: David Seidman
• 金额: $ 39.09万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2105362&HistoricalAwards=false
• 关键词: NSF; BSF; Influence; cohesion; enhancing

Non-Technical Summary:Exposure of steels to hydrogen (1H) during manufacturing, storage or service may embrittle them, potentially resulting in catastrophic failures. Therefore, hydrogen embrittlement (HE) of steels is of concern in 1H energy systems, automobiles, aviation, marine applications, bridges, transportation infrastructure, and nuclear reactors. 1H concentrations in the atomic ppm range are sufficient to embrittle high-strength steels. 1H trapping at defects, grain boundaries, heterophase interfaces, and elastic stress-fields, affects its solubility, diffusivity, and the susceptibility of steels to HE. Additively manufactured (AM) steels may be more susceptible to HE than their counterpart wrought steels due to different microstructures, porosity levels, and residual stress levels. The understanding of 1H ingress, local concentrations, trapping vs. mobile 1H, and its 3D spatial distributions, is important for chemical and microstructural design of next-generation, hydrogen-resistant steels. The PIs are proposing a systematic study starting with the design of a novel precipitation-hardened stainless steel for selective laser melting; controlled powder synthesis and characterization; AM of steels by both powder-bed fusion SLM and directed energy deposition laser engineered net shaping; chemical, microstructural, and mechanical characterization of AM steels compared to their wrought counterpart steel, before and after 1H or 2D electrochemical charging. Scientific and technological strategies and alloy design principles will directly support the development of AM for industrial manufacturing. The scientific and technological strategies and alloy design principles will support the development of AM for industrial manufacturing. Our projects will provide multi-dimensional training for students and postdocs, including processing-structure-properties relationships, the fundamental paradigm of materials science & engineering, physical metallurgy and alloy design, advanced atomic-level structural/chemical characterization, first-principles calculations, HE, mechanical properties evaluation and failure analysis.Technical Summary:The overarching scientific theme of the proposed research is to understand the effects of different elements, impurities and either 1H or 2D, on the cohesive energies of GBs and heterophase interfaces concerning HE in AM materials, focusing on PH stainless steels derived from the classical 17-4 PH steel. Wrought 17-4PH steel is included to provide a reference basis for comparison with the AM processed steels, i.e., QT17-4+. This will enable us to better understand the influence of grain- and heterophase-boundary segregation of alloying elements, impurities, and 1H or 2D, and the effects of different processing conditions (e.g., heating rates) on the microstructures (GB characteristics of martensite lath and prior austenite grain-boundaries), GB cohesion, and susceptibility to HE. From this detailed understanding, we will develop mitigation strategies for embrittlement of AM and/or welded components and use alloy design principles to optimize interfacial cohesion of the defects critical for HE. The fundamental data generated will pave the way to next-generation steel designs and support the industrial revolution created by the development of AM. The PIs will develop an online graduate-level course, Additive Manufacturing of Metallic Materials: Theory and Practice, for teaching at Tel Aviv University and Northwestern. Students will form groups of four and apply topics learned to a rapid manufacturing design project. Students will gain significant experience with writing and presenting to a technical audience. At NUCAPT, the PIs will continue undergraduate student projects through the NSF-REU programs of the NSF-funded Materials Research Science and Engineering Center, SHyNE resource, programs aimed at women and underrepresented minorities, work-study and senior project students, national universities, national laboratories, and industry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：在制造，存储或服务过程中，钢暴露于氢（1H）可能会释放它们，可能导致灾难性的失败。因此，在1H能源系统，汽车，航空，海洋应用，桥梁，运输基础设施和核反应堆中，钢的氢含水（HE）引起了关注。原子PPM范围内的1H浓度足以结合高强度钢。 1H捕获在缺陷，晶界，异物相界面和弹性应力场上会影响其溶解度，扩散性和钢对He的敏感性。由于微观结构，孔隙率水平和残留应力水平，添加性生产（AM）钢可能比其对应物钢钢更容易受到他的影响。对1H入学，局部浓度，捕获与移动1H的了解及其3D空间分布对于下一代耐氢的钢的化学和微观结构设计很重要。 PIS提出了一项系统的研究，从设计新颖的降水耐不锈钢进行选择性激光融化开始。受控的粉末合成和表征；由粉末床融合SLM和定向能量沉积激光工程净成型的钢的Am Am Am Am of Steels；与锻造的钢相比，AM钢的化学，微观结构和机械表征，1H或2D电化学充电之前和之后。科学和技术策略以及合金设计原则将直接支持用于工业制造的AM的开发。科学和技术策略以及合金设计原则将支持为工业制造的AM开发。我们的项目将为学生和博士后提供多维培训，包括处理结构 - 实验关系，材料科学与工程的基本范式，物理冶金和合金设计，先进的原子级结构/化学/化学/化学特征，第一些原理计算，HE HE，机械属性和失败分析。元素，杂质以及1H或2D，在GB和异偶体界面的凝聚力上，涉及AM材料中的元素，重点是源自经典17-4 pH钢的pH不锈钢。包括17-4ph钢的锻造，以提供与AM加工钢的比较的参考基础，即QT17-4+。这将使我们能够更好地理解合金元素，杂质和1H或2D的谷物和异物构成分离的影响，以及不同加工条件（例如供暖速度）对微观结构（Martsenite Lath和Martsenite Lath和先前的Austenite Grainite Grainite Grainite Grainite grainite grainite grainite Grainite），GB Cohemigiention，以及Sustipientions和Sustistibility的影响。从这种详细的理解中，我们将制定缓解策略，以覆盖AM和/或焊接组件，并使用合金设计原理来优化对HE至关重要的缺陷的界面凝聚力。生成的基本数据将为下一代钢设计铺平道路，并支持AM的发展创造的工业革命。 PI将开发在线研究生级课程，金属材料的添加剂制造：理论和实践，用于特拉维夫大学和西北部的教学。学生将组成四组，并将学到的主题应用于快速制造设计项目。学生将获得写作和向技术受众展示的丰富经验。在Nutapt中，PI将继续通过NSF-REU计划，NSF-REU计划的NSF-REU计划，由NSF资助的材料研究科学和工程中心，Shyne资源，针对妇女和代表性不足的少数群体，工作实习生和高级项目学生，国家大学，国家大学，国家实验室和行业的计划均反映了NSF的范围，这是NSF的Infortional Merit，该奖项的范围是宽广的，该奖项反映了NSF的范围，该奖项的范围是范围的范围。影响审查标准。