Crystallographic Textures Induced by Dry Sliding Wear in Metals

金属干滑动磨损引起的晶体织构

• 批准号: 0906703
• 负责人: Pascal Bellon
• 金额: $ 31.5万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0906703&HistoricalAwards=false
• 关键词: Crystallographic; Textures; Induced; Dry; Sliding

This Award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).TECHNICAL SUMMARY:The crystallographic textures generated by dry sliding wear in metallic elements and alloys are investigated in this project. These crystallographic textures develop in the severely plastically deformed (SPD) nanograin layers that are produced by wear just below the sliding surfaces, and extend over a depth of the order of one micrometer. In contrast to textures produced by metal-forming processes such as rolling, drawing, or extrusion, there is only partial and scattered data on wear-induced textures. This is despite the fact that texture is known to affect friction and wear. The main objectives of this research are firstly to investigate systematically the effects of wear parameters, such as load, sliding velocity, and temperature, and material parameters, such as twinning tendency and initial grain size, on texturing. Textures are evaluated by electron backscattering diffraction in scanning electron microscopy (SEM) and by transmission electron microscopy (TEM). Secondly, since standard methods do not provide a direct measurement of plastic strain in the SPD layer owing to grain fragmentation, a specific method is implemented where pre-existing nanoscale precipitates are used as markers. TEM characterization of the precipitate shape evolution provides direct measurement of plastic strain. Thirdly, the mechanical properties of the textured nanograined layers are determined by combining indentation and scratch tests, both at the micro and nanoscale using nanotribometry. Integration of all these results will contribute to designing a strategy to select materials with improved friction and wear response by taking advantage of the crystallographic texturing induced by sliding wear. The impact of the proposed research is broadened by developing and integrating 2 modules, one on wear and the other one on texture, into an existing senior laboratory course and by providing research experience for undergraduate students. The research also benefits from an international collaboration with Prof. Chevalier (France) on texture induced by severe plastic deformation.NON-TECHNICAL SUMMARY:Premature wear is the primary cause of failure of many mechanical systems, leading to losses estimated to well over 100 billion dollars in the U.S. alone. The development of materials with lower friction coefficient and improved wear resistance could reduce these losses as well as improve energy consumption. To that end, the present research aims at developing the knowledge and understanding of the crystallographic textures, i.e. the distribution of crystallographic orientations of grains in a polycrystalline material, that are stabilized by dry sliding wear in metallic materials. While texture control is widely used in industry to optimize the processing and the properties of use of materials, lack of knowledge has prevented until now the application of a similar approach to guide the design and the selection of wear resistant materials. The proposed research attempts to bridge this knowledge gap by taking advantage of important advances in characterization techniques such as orientation imaging microscopy and transmission electron microscopy, as well as in nanoscale mechanical testing. The research will provide education for one graduate and three undergraduate students in the important technological field of wear. Special effort will be made to recruit female and underrepresented minority students. An international collaboration with Prof. Chevalier (France) will also be established.

该奖项是根据2009年的《美国回收与再投资法》（公法111-5）进行的。技术摘要：在该项目中调查了金属元素和合金的干滑动磨损产生的晶体学纹理。这些晶体学纹理在严重的塑料变形（SPD）纳米层中形成，这些纳米含量是由滑动表面下方的磨损产生的，并延伸到一个千分尺的深度上。与金属形成过程（例如滚动，绘图或挤出）产生的纹理相反，磨损诱导的纹理只有部分和分散的数据。尽管质地众所周知会影响摩擦和磨损。这项研究的主要目标首先是系统地研究磨损参数的影响，例如负载，滑动速度，温度以及材料参数，例如孪生趋势和初始晶粒尺寸，对纹理。通过电子反向散射衍射（SEM）和透射电子显微镜（TEM）评估纹理。其次，由于由于晶粒碎片化，标准方法不能直接测量SPD层中的塑性应变，因此在将预先存在的纳米级沉淀物用作标记的情况下实现了一种特定的方法。沉淀形状演化的TEM表征可直接测量塑性应变。第三，使用纳米伯尺度在微观和纳米级，通过结合压痕和刮擦测试来确定纹理纳米层的机械性能。所有这些结果的整合将有助于设计一种策略，以利用滑动磨损引起的晶体学纹理，从而选择具有改善摩擦和磨损反应的材料。通过开发和集成了2个模块，一个对磨损，另一个对质地的模块进行扩展，将拟议研究的影响扩大到现有的高级实验室课程中，并为本科生提供研究经验。这项研究还受益于与Chevalier教授（法国）关于严重塑性变形引起的质地的国际合作。没有技术摘要：早熟是许多机械系统失败的主要原因，导致估计估计超过1000亿的损失仅在美国，美元。开发具有较低摩擦系数和改善耐磨性的材料可以减少这些损失并改善能源消耗。为此，本研究的目的是发展对晶体学纹理的知识和理解，即多晶材料中晶粒的晶体学取向的分布，这些材料通过金属材料中的干滑动磨损稳定。虽然纹理控制在行业中广泛用于优化材料使用的加工和特性，但直到现在，缺乏知识一直无法使用类似的方法来指导设计和选择耐磨性材料。拟议的研究试图通过利用特征技术的重要进展，例如方向成像显微镜和透射电子显微镜以及纳米级机械测试来弥合这一知识差距。这项研究将为重要的技术领域的一名研究生和三名本科生提供教育。将要努力招募女性和代表性不足的少数民族学生。还将与Chevalier教授（法国）进行国际合作。