Collaborative Research: In situ Diffraction and Cohesive-Zone Studies of the Fatigue-Crack-Growth Behavior in Mg Alloys

合作研究：镁合金疲劳裂纹扩展行为的原位衍射和内聚区研究

• 批准号: 1809640
• 负责人: Yanfei Gao
• 金额: $ 37.5万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1809640&HistoricalAwards=false
• 关键词: Collaborative; Research; situ; Diffraction; Cohesive

Non-Technical Abstract: The accelerated adoption of magnesium alloys as structural components in the automobile and aerospace industry is driven by their unique properties of low density, high strength-to-weight ratio, and high specific stiffness. However, the fatigue properties of magnesium alloys and associated failure mechanisms have not been well-characterized, which severely limits the technological viability of these lightweight alloys. This award supports the fundamental research to provide the microstructural-level understanding of the failure processes, which ultimately govern the fatigue life of magnesium alloys. The research will pave the way towards the intelligent design of advanced, lightweight structural alloys with the improved fatigue life. In the broader sense, this research will impact the aerospace and automotive industries and would help U.S. improve its manufacturing competitiveness. The unique experimental and modeling tools will help enrich the current course curriculum on mechanics and materials at both the University of Tennessee and University of Illinois. A demonstrative toolkit will expose high school students at both universities to concepts of fracture and failure, and how crack stopping mechanisms can be introduced to improve fatigue life.Technical Abstract:The goal of this research is to couple fatigue-crack-growth studies of magnesium alloys, with in situ nondestructive measurements and micromechanical modeling investigations, which will establish the connection between microscopic failure processes and macroscopic fatigue-crack-growth properties. The primary objective is to identify the roles of the surrounding plasticity and crack-tip process zones in the resistance to fatigue-crack growth of magnesium alloys. Within the surrounding plastic zone, in situ neutron-diffraction measurements and high-energy synchrotron X-ray diffraction techniques will provide the unprecedented information on plastic anisotropy, twin polarity, flow non-normality, and texture evolution in magnesium alloys under the arbitrary stress multiaxiality. Within the process zone, which is inaccessible to experimental measurements, a novel nonlinear field projection scheme will be used to inversely reconstruct the cohesive zone laws for fatigue-crack growth uniquely from the surrounding deformation fields that are measured by the diffraction experiments. By linking top-down stress analyses with bottom-up failure mechanisms at inter- and intra-granular scales, this fundamental research can lead to predictive models based on microstructural understanding with which materials scientists can utilize to improve the fatigue life of advanced structural alloys.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：加速采用镁合金作为汽车和航空航天行业中的结构成分，是由它们的低密度，高强度重量比和高特异性刚度的独特特性所驱动的。但是，镁合金的疲劳特性和相关的失效机制尚未得到充分的特征，这严重限制了这些轻质合金的技术生存能力。该奖项支持基本研究，以提供对故障过程的微观结构水平的理解，该过程最终控制了镁合金的疲劳寿命。这项研究将为智能设计的智能设计铺平道路，并具有改善的疲劳寿命。从广义上讲，这项研究将影响航空航天和汽车行业，并将帮助美国提高其制造业竞争力。独特的实验和建模工具将有助于丰富田纳西大学和伊利诺伊大学的机械师和材料课程。一个示范性的工具包将使两所大学的高中生都面临着骨折和失败的概念，以及如何引入裂缝停止机制以改善疲劳寿命。技术摘要：这项研究的目的是使镁的疲劳性酸化研究对镁进行。合金，具有原位的无损测量和微机械建模研究，这将建立微观衰竭过程与宏观疲劳 - 裂缝增长特性之间的联系。主要目的是确定周围塑性和裂纹尖端过程区域在耐镁合金疲劳裂缝生长中的作用。在周围的塑料区域内，原位中子划分测量和高能量同步加速器X射线衍射技术将提供有关塑料各向异性，双极性，非正常性和质地演化的前所未有的信息。 。在实验测量无法访问的过程区域内，新型的非线性场投影方案将用于反向重建粘性区定律，以独特地从衍射实验测量的周围变形场中独特地重建疲劳性生长。通过将自上而下的应力分析与粒间尺度和粒状尺度下的自下而上的失败机制联系起来，这项基本研究可以基于微结构理解，从而导致预测模型科学家可以利用材料来改善先进结构合金的疲劳寿命。该奖项反映了NSF的法定使命，并通过使用基金会的知识分子和更广泛的影响审查标准进行评估而被认为值得支持。

项目成果

Triaxial Constraint and Tensile Strength Enhancement in Brazed Joints

• DOI: 10.1007/s11661-020-05984-x
• 发表时间: 2020-09
• 期刊: Metallurgical and Materials Transactions A
• 作者: Xin Cai;Yanfei Gao;Xue Wang;Wei Zhang;Wei Liu;Xinpu Shen;Wei Zhang;Zhenzhen Yu;Zhili Feng

Mechanical behaviors of equiatomic and near-equiatomic face-centered-cubic phase high-entropy alloys probed using in situ neutron diffraction

• DOI: 10.1016/j.ijplas.2022.103417
• 发表时间: 2022-09
• 期刊: International Journal of Plasticity
• 影响因子: 9.8
• 作者: Daixiu Wei;W. Gong;T. Tsuru;T. Kawasaki;S. Harjo;B. Cai;P. Liaw;Hidemi Kato

A physics-based machine-learning approach for modeling the temperature-dependent yield strengths of medium- or high-entropy alloys

• DOI: 10.1016/j.apmt.2023.101747
• 发表时间: 2023-04
• 期刊: Applied Materials Today
• 影响因子: 8.3
• 作者: Baldur Steingrimsson;Xuesong Fan;R. Feng;P. Liaw

Investigation of chaos and memory effects in the Bonhoeffer-van der Pol oscillator with a non-ideal capacitor

• DOI: 10.1016/j.cnsns.2019.01.019
• 发表时间: 2018-03
• 期刊: Commun. Nonlinear Sci. Numer. Simul.
• 作者: J. Brechtl;Xie Xie-Xie;P. Liaw

Recent progress in oxidation behavior of high-entropy alloys: A review

• DOI: 10.1063/5.0116605
• 发表时间: 2022-12
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: Poresh Kumar;T. Lam;P. Tripathi;S. Singh;P. Liaw;E. Huang