Understanding Precipitation and the Mechanical Properties of Novel Laves Phase-Strengthened Austenitic Steels for Energy Applications

了解用于能源应用的新型 Laves 相强化奥氏体钢的析出和机械性能

• 批准号: 1206240
• 负责人: Ian Baker
• 金额: $ 40.5万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206240&HistoricalAwards=false
• 关键词: Understanding; Precipitation; Mechanical; Properties; Novel

TECHNICAL SUMMARYThis project aims to understand both the effects of deformation on the precipitation processes in Laves phase-strengthened austenitic steels, including determining the mechanism of NiAl co-precipitation, and how these two kinds of precipitates affect subsequent deformation processes. Thus, the proposed work will determine both the precipitation mechanisms and the interaction of gliding dislocations with these precipitates by performing annealing studies for a variety of times and temperatures, both with and without prior cold rolling, and both room-temperature tensile tests and elevated-temperature creep tests on these materials followed by post-mortem TEM examination. The fracture behavior will also be examined by performing in-situ straining studies at a variety of temperature in a scanning electron microscope. The orientation relationships between the phases both after various thermo-mechanical treatments and after creep deformation will be carefully studied using electron diffraction, while the microchemistry will be determined using both energy dispersive spectroscopy in the TEM and atom probe tomography. The precipitation processes and the deformation mechanisms will be further elucidated by performing in situ annealing studies and in situ straining studies in the TEM, respectively, at a variety of temperatures. The work will be performed by a Ph.D. student and several undergraduates.NON-TECHNICAL SUMMARYThe critical factor limiting the operation of power generation plants at higher temperatures is the lack of materials that are strong, corrosion resistant and economically viable. Operation at high temperature can lead to energy conversion efficiencies of 50%, which not only reduces running costs, but can also extend the lifetime of fossil fuels and/or reduce the carbon footprint of the plants. Unfortunately, currently-used steels cannot satisfy these requirements for higher operating temperatures. This project aims to determine the optimum processing condition and mechanical properties in new class of stainless steels strengthened with novel particles, and alloyed with aluminum for improved oxidation resistance. A Ph.D. student and several undergraduates are performing the work.

技术摘要项目旨在了解变形对LAVES加长的奥氏体钢的降水过程的影响，包括确定NIAL共同沉积的机制，以及这两种降水量如何影响随后的变形过程。因此，拟议的工作将通过对有或没有以前的冷滚动的各种时间和温度进行退火研究，以及室温的拉伸测试和升高 - 对这些材料进行温度蠕变测试，然后进行验尸后TEM检查。还将通过在扫描电子显微镜下在各种温度下进行原位的拉伸研究来检查断裂行为。 各种热力学处理和蠕变变形后，相位之间的方向关系将使用电子衍射仔细研究，而微化学将使用TEM和原子探针断层扫描中的能量分散光谱确定微化学。 通过在各种温度下，将分别在TEM中进行原位退火研究和原位过滤研究，将进一步阐明降水过程和变形机制。这项工作将由博士学位。学生和几个本科生。没有技术总结，限制发电厂在较高温度下运行的关键因素缺乏强烈，耐腐蚀且经济上可行的材料。在高温下的运行可以导致50％的能源转化效率，这不仅可以降低运行成本，而且还可以延长化石燃料的寿命和/或降低植物的碳足迹。 不幸的是，目前使用的钢无法满足这些对更高工作温度的要求。 该项目旨在确定新型不锈钢的最佳加工条件和机械性能，并用新型颗粒加强，并与铝合金，以提高氧化耐药性。博士学生和几名大学生正在执行这项工作。