Fatigue and deformation aspects of lightweight materials

轻质材料的疲劳和变形方面

• 批准号: 249748-2011
• 负责人: Chen, Daolun
• 金额: $ 4.01万
• 依托单位: Ryerson University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=570713
• 关键词: Fatigue; deformation; aspects; lightweight; materials

In today's rapidly evolving energy crisis, improvements in fuel efficiency and reductions in greenhouse gas emissions are prime concerns and urgent topics to be solved in the automotive and aerospace industries. Lightweighting is one of the most important strategies, with every 10% reduction in weight leading to a 6.6% to 8% increase in fuel efficiency. Magnesium is the lightest of structural metals - it weighs 75% less than steel and is about one third lighter than aluminum. It is now regarded as a strategic lightweight material in the automotive and aerospace sector. However, there exist a number of issues that severely limit the widespread applications of magnesium alloys, including fatigue and reliability, welding and joining, corrosion resistance, and formability. Other issues remain as to how the twinning and detwinning occur during cyclic deformation, and if the anisotropy and strong tension-compression yield asymmetry in wrought magnesium alloys can be reduced or eliminated. The objectives of the proposed research are to address these critical issues and barriers building upon the applicant's extensive and pioneering research experience and knowledge in this area, and develop a fundamental understanding of fatigue and fracture of magnesium alloys and other types of lightweight materials. Specifically, the following topics will be examined: i) the underlying fatigue deformation and twinning-detwinning mechanisms in wrought magnesium alloys will be elucidated and modeled, ii) the texture and residual stresses will be analyzed and evaluated using a unique high-temperature X-ray diffractometer which permits in-situ measurements as a function of temperatures, iii) the effect of welding and protective coatings on fatigue deformation resistance will be examined, iv) new processing approach and models will be developed to weaken textures and reduce anisotropy. These projects will improve fundamental understanding of long-term performance in magnesium alloys, provide a basis for further development of lightweight alloys for aerospace, automotive and electronic applications, and lead to the training of Ph.D. and master's students who are in high demand from industry, academe, and government laboratories.

在当今迅速发展的能源危机中，提高燃料效率和减少温室气体排放是汽车和航空航天工业的首要关注点和迫切需要解决的课题。轻量化是最重要的策略之一，重量每减少10%，燃油效率就能提高6.6%至8%。镁是最轻的结构金属-它比钢轻75%，比铝轻约三分之一。它现在被视为汽车和航空航天领域的战略性轻质材料。然而，镁合金在疲劳与可靠性、焊接与连接、耐腐蚀性和成形性等方面存在着许多问题，严重限制了镁合金的广泛应用。其他问题仍然是如何在循环变形过程中发生的孪生和去孪生，以及是否可以减少或消除变形镁合金中的各向异性和强拉伸-压缩屈服不对称性。拟议研究的目标是解决这些关键问题和障碍，建立在申请人在这一领域的广泛和开创性的研究经验和知识，并发展镁合金和其他类型的轻质材料的疲劳和断裂的基本理解。具体而言，将审查以下专题：i）将阐明和模拟变形镁合金中潜在的疲劳变形和孪生-去孪生机制，ii）将使用独特的高温X射线衍射仪分析和评估织构和残余应力，该衍射仪允许作为温度的函数进行原位测量，iii）将研究焊接和保护涂层对抗疲劳变形的影响，iv）将开发新的加工方法和模型以削弱织构和减少各向异性。这些项目将提高对镁合金长期性能的基本理解，为进一步开发用于航空航天，汽车和电子应用的轻质合金提供基础，并培养博士学位。以及工业界、企业界和政府实验室对硕士生的需求量很大。