The Influence of Stacking Fault Energy on the Phase Transformations and Deformation Mechanisms in Iron-Manganese Alloys

堆垛层错能对铁锰合金相变和变形机制的影响

• 批准号: 0805295
• 负责人: James Wittig
• 金额: $ 21万
• 依托单位: Vanderbilt University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0805295&HistoricalAwards=false
• 关键词: Influence; Stacking; Fault; Energy; Phase

TECHNICAL: Austenitic Fe-Mn alloys have exceptional mechanical properties. Recent trends in the automotive industry towards improved safety standards, reduced weight, and cost effective manufacturing have led to a renewed interest in these high strength and ?super tough? steels. Alloys of Fe-Mn exhibit extensive ducility and strength over a large temperature range (-200 to 250 C) where low temperature deformation can show elongation 75% and ultimate tensile strength over 1000 MPa. These outstanding mechanical properties are produced by the transformation induced plasticity (TRIP) effect, which is related to the low intrinsic stacking fault energy (SFE) in austenitic steels. The additions of elements such as Al, Si, C, and N have large influences on both the SFE and deformation mechanism. Temperature dependent plasticity can change from TRIP to twinning induced plasticity (TWIP) when the SFE is affected. Although extensive work has been performed in this area over the last 50 years, there is still a considerable lack of understanding and disagreement for the underlying factors that determine whether the temperature dependent deformation mechanism will be dislocation glide, strain induced martensite, or mechanical twinning. The research is a systematic study with model FeMn(AlSi) and FeMnC alloys as well as more complex high Mn-N stainless steel materials to investigate the influence of alloys elements (Mn, Al, Si, C, N) on the SFE for these austenitic materials. A major objective of the research is the development of structure property relationships between quantitative measurements of SFE as a function of composition and temperature and the temperature dependent mechanical deformation mechanisms for austenitic Fe-Mn alloys. These fundamental studies will provide the basis for optimizing the Fe-Mn alloy composition to achieve improved mechanical properties in new commercial alloys. NON-TECHNICAL: The research involves collaboration between Vanderbilt University, the Max-Planck Institut fur Eisenforschung, and Oak Ridge National Laboratory. This collaboration will not only serve to make a strong scientific approach to the research, it will also provide an educational component to the program where both graduate students and undergraduate students will be exposed to international interactions and state-of-the-art facilities at a national laboratory. Undergraduates will be involved in this program with both senior independent research opportunities and summer internships. Graduate students involved in this program will receive the training required to pursue a career in Materials Science and Engineering. A second objective of the current project is to train underrepresented groups as future scientists. The P.I. of this project (co-PI for the Vanderbilt/Fisk IGERT program and director of the Vanderbilt Interdisciplinary Materials Science Program) is dedicated to increasing the diversity of the Vanderbilt Ph.D. program. He is currently the principal advisor for one of the Vanderbilt/Fisk IGERT minority students, and this NSF funded program would provide for future support of new Fisk masters students interested in a Vanderbilt Ph.D. The research program has the potential to make major contributions to the education, training and knowledge of future scientists.

技术：奥氏体铁锰合金具有优异的机械性能。汽车行业最近的趋势是提高安全标准，减轻重量和成本效益的制造，这导致了对这些高强度和低强度材料的重新兴趣。超级强硬?钢。Fe-Mn合金在较大的温度范围内（-200℃至250℃）表现出广泛的延展性和强度，其中低温变形可以显示75%的伸长率和超过1000 MPa的极限拉伸强度。这些优异的力学性能是由相变诱发塑性（TRIP）效应产生的，这与奥氏体钢的低本征层错能（SFE）有关。Al、Si、C、N等元素的加入对材料的SFE和变形机制都有较大的影响。当SFE受到影响时，材料的温度依赖塑性由TRIP转变为TWIP。尽管在过去的50年里，在这一领域进行了大量的工作，但对于决定温度相关变形机制是位错滑动、应变诱发马氏体还是机械孪晶的潜在因素，人们仍然缺乏理解和分歧。本研究以模型FeMn（AlSi）和FeMnC合金以及更复杂的高Mn-N不锈钢材料为研究对象，系统研究了合金元素（Mn、Al、Si、C、N）对这些奥氏体材料SFE的影响。本研究的一个主要目标是发展奥氏体Fe-Mn合金的SFE定量测量作为成分和温度的函数与温度相关的机械变形机制之间的组织性能关系。这些基础研究将为优化Fe-Mn合金成分以改善新型商用合金的力学性能提供依据。非技术：这项研究涉及范德比尔特大学、马克斯-普朗克研究所和橡树岭国家实验室的合作。这种合作不仅将为研究提供强有力的科学方法，还将为该项目提供教育组成部分，使研究生和本科生都能接触到国际交流和国家实验室最先进的设施。本科生将参与该项目，包括高级独立研究机会和暑期实习机会。参与本课程的研究生将接受从事材料科学与工程职业所需的培训。当前项目的第二个目标是培训代表性不足的群体成为未来的科学家。该项目的私家侦探（范德比尔特/菲斯克IGERT项目的联合私家侦探和范德比尔特跨学科材料科学项目的主任）致力于增加范德比尔特博士项目的多样性。他目前是范德比尔特/菲斯克IGERT少数民族学生的主要顾问，这个NSF资助的项目将为对范德比尔特博士感兴趣的新菲斯克硕士学生提供未来的支持。该研究项目有可能为未来科学家的教育、培训和知识做出重大贡献。