Collaborative Research: Improving contact fatigue and wear properties using graded nanostructured surfaces in metallic materials

合作研究：使用金属材料中的分级纳米结构表面改善接触疲劳和磨损性能

• 批准号: 2004556
• 负责人: Ming Dao
• 金额: $ 24.67万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004556&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; contact; fatigue

Non-technical summaryGraded nanostructured metallic materials, with grain-size gradients ranging from the nanometer-level in the surface regions to the micrometer-level in the interior regions, are a novel class of materials that have exhibited promise for exceptional mechanical properties. However, at present, there is very limited understanding of the surface wear resistance and contact fatigue behavior of these nano-graded metals and alloys. Unlike in the case of materials with a uniform grain-size, where the surface region provides only one type of surface wear protection, in the nano-graded materials, the surface region has the potential to provide two types of protections by increasing the resistance to both damage initiation and subsequent damage progression into the interior of the material. Through modeling and experiments, this collaborative project between Stony Brook and MIT, seeks to obtain a scientific understanding of damage initiation and damage evolution processes in metallic materials with graded nanostructured surfaces. By advancing the current understanding of the mechanisms associated with surface wear protection and contact fatigue resistance of graded nanostructured materials, this project facilitates the development of a road-map for the reliable introduction of novel materials in the multi-billion dollar tribology industry that includes aircraft, automotive, electronic packaging, nuclear energy, and biomedical applications. Technical SummaryThis project is focused on obtaining a fundamental understanding of the contact fatigue crack resistance in graded nanostructured metallic materials. In particular, the influence of dislocation activities that are dictated by grain-size gradients and yield strength gradients, on crack tip blunting and crack tip shielding, is assessed. An adhesion-based analytical modeling framework is developed to predict the conditions for contact fatigue crack initiation in graded nanomaterials. A dislocation pile-up based multi-scale plasticity model is implemented in finite elements to predict contact fatigue damage evolution pathways in graded nanostructured metals and alloys. Contact fatigue and wear experiments are designed to provide a quantitative assessment of contact fatigue and wear behavior of graded nanomaterials and validation for the analytical and numerical models developed, while microstructural observations identify deformation mechanisms that contribute to contact fatigue resistance and wear damage protection. A new design paradigm for engineering functionally-graded nanomaterials that provides enhancements in contact fatigue damage resistance, beyond the classical limit that has been traditionally obtained in materials with (mostly uniform) surface modified layers, is identified.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.

非技术总结的纳米结构金属材料，晶粒大小的梯度从地面区域的纳米级层到内部区域的微米水平，是一类新型的材料，它们对出色的机械性能表现出了希望。但是，目前，对这些纳米级金属和合金的表面耐耐受性和接触疲劳行为的了解非常有限。与具有均匀晶粒尺寸的材料的情况不同，在纳米级材料中，表面区域仅提供一种类型的表面磨损保护，而表面区域有可能通过增加对两种类型的保护。损害的启动和随后的损害进展为材料内部。通过建模和实验，Stony Brook和MIT之间的合作项目旨在获得对具有分级纳米结构表面的金属材料中的损伤开始和损伤进化过程的科学理解。通过促进对与表面磨损保护和分级纳米结构材料的抗疲劳抗性相关的机制的理解，该项目有助于开发路线图，以可靠地在包括飞机在内的数十亿美元摩擦学中可靠地引入新型材料，汽车，电子包装，核能和生物医学应用。技术摘要项目的重点是对分级纳米结构金属材料的接触疲劳裂纹抗性获得基本了解。特别是，评估了由晶粒大小梯度和产量强度梯度决定的位错活动的影响，对裂纹尖端钝和裂纹尖端屏蔽的影响。开发了基于粘附的分析建模框架，以预测分级纳米材料中接触疲劳裂纹启动的条件。在有限的元素中实现了基于位错堆积的多尺度可塑性模型，以预测分级纳米结构金属和合金中的接触疲劳损伤进化途径。接触疲劳和磨损实验旨在提供对纳米材料的接触疲劳和磨损行为的定量评估，并为开发的分析和数值模型进行验证，而微结构观察结果则确定了有助于接触疲劳阻力和磨损损害保护的变形机制。一个新的设计范式，用于工程功能分级的纳米材料，可提供接触疲劳损伤的增强功能，超出传统上具有（大多数均匀）表面修饰层的材料中获得的经典限制，这反映了NSF的法定任务，并具有法定任务使用基金会的知识分子优点和更广泛的审查标准，被认为值得通过评估来支持。