Optimization of phase transformation for the development of fatigue resistant materials

优化相变以开发抗疲劳材料

• 批准号: RGPIN-2014-05127
• 负责人: Brochu, Myriam
• 金额: $ 1.82万
• 依托单位: École Polytechnique de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=681013
• 关键词: Optimization; phase; transformation; development; fatigue

The development of materials with improved fatigue resistance and their characterization methods is a growing field of research as it allows the optimization of engineering components without compromising safety. One original way to improve the fatigue resistance of metals is to optimize the benefits of phase transformation during the propagation of cracks. The survey of literature reveals that phase transformation can increase fatigue strength by 50% in some specific conditions. The main benefits of phase transformation are to consume mechanical energy and to produce compressive residual stresses closing the crack tip. On the other hand, phase transformation under cyclic loads is complex and its efficiency is influenced by several parameters such as the environment, the microstructure, the loading conditions. A better understanding of 1) the thermodynamic and kinetic of phase transformation at crack tip, and 2) its effect on the crack propagation mechanisms, could lead to the development of advanced materials with improved fatigue resistance. These are the objectives of my discovery grant program.* *At completion of the first five years, the knowledge and experimental results I will have developed will easily be extended to engineering applications such as the optimization of steels for fatigue critical applications (e.g. hydraulic turbine runners and landing gears) and the control of mechanical and environmental conditions to avoid catastrophic failures. This is of significant importance for many local and global industries with whom I am currently collaborating (e.g. Hydro-Quebec, Alstom, Velan and Héroux Devtek). The societal role of my research program is to contribute to the reduction of fuel consumption and green house emissions as the developed materials will be used to design lighter products. **The proposed research program is unique as it seeks a deep understanding and control of phase transformation at crack tip, under cyclic loads in a variety of environments. Very limited work on this topic has been published as such phase transformations are conventionally used to improve the ductility and toughness of materials under monotonic stresses. The specificity of my research programs relies on the interest I have toward the quantification and understanding of fatigue damage mechanisms and their relation to the material microstructure. Such a detail research tackling multidisciplinary challenges, in mechanical and material engineering, has not been performed yet.**My team has the skills and knowledge necessary to perform the proposed work as we have been working on the fatigue behavior of metallic materials since 2006 and on failure analysis since 2001. We have developed a variety of advanced experimental and analytical strategies to measure, observe and understand fatigue failure mechanisms in metals and more specifically in steels and aluminum alloys. In the province of Quebec, I am considered by my peers and by industrial partners one of the most experimented researcher on the topic. **Finally, the research program I propose will contribute to the training of 4 highly qualified engineers and 5 interns that will acquire skills and knowledge in physical metallurgy, failure analysis and fracture mechanic. This type of background is prized in Quebec, especially by the aerospace, transport and energy industries. This type of training has unfortunately been uncovered in Quebec during the last five years especially with the closure, in 2008, of the material science undergraduate program of Ecole Polytechnique de Montreal. The impact of loosing this specialized formation at the undergraduate level is giving a plus value to my contribution to knowledge and to the originality of my training program.

具有改善疲劳性抗性及其表征方法的材料的开发是一个不断增长的研究领域，因为它允许在不损害安全性的情况下优化工程组件。提高金属疲劳性抗性的一种原始方法是优化裂缝传播过程中相变的益处。文献调查表明，在某些特定条件下，相转化可以使疲劳强度提高50％。相变的主要好处是消耗机械能并产生关闭裂纹尖端的复杂残余应力。另一方面，循环载荷下的相变很复杂，其效率受环境，微结构和加载条件等多个参数的影响。更好地了解1）裂纹尖端时相变的热力学和动力学，以及2）其对裂纹传播机制的影响可能导致具有改善疲劳性抗性的高级材料的发展。这些是我发现赠款计划的目标。对于我目前正在与之合作的许多本地和全球行业（例如Hydro-Quebec，Alstom，Velan和HérouxDevtek）至关重要。我的研究计划的社会作用是为减少燃料消耗和温室排放做出贡献，因为开发材料将用于设计较轻的产品。 **拟议的研究计划是独一无二的，因为它在各种环境中的环状负载下寻求对裂纹尖端的相变的深刻理解和控制。该主题的工作非常有限，因为通常使用这种相转换来改善单调应力下材料的延展性和韧性。我的研究计划的特异性取决于我对疲劳损伤机制的量化和理解及其与材料微观结构的关系的兴趣。在机械和材料工程领域，尚未进行此类详细的研究，以应对多学科挑战，尚未进行。合金。在魁北克省，我的同龄人和工业伙伴认为我是该主题最受实验的研究人员之一。 **最后，我提出的研究计划将有助于对4位高素质的工程师和5名实习生进行培训，这些工人将获得物理冶金，失败分析和断裂机械的技能和知识。这种背景在魁北克备受赞誉，尤其是航空航天，运输和能源行业。不幸的是，在过去的五年中，魁北克发现了这种类型的培训，尤其是在2008年关闭蒙特利尔的材料科学本科课程的关闭中。在本科层面上失去这种专业的编队的影响是我对知识和培训计划的独创性的贡献的基础。