U.S.-Czech Engineering Research on Dislocation Substructure and Crack-Tip Blunting on the Brittle-to-Ductile Transition in Iron and Structural Steels

美国-捷克关于铁和结构钢脆性到延性转变的位错亚结构和裂纹尖端钝化的工程研究

• 批准号: 9707863
• 负责人: Glenn Beltz
• 金额: $ 1.16万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 1999-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9707863&HistoricalAwards=false
• 关键词: U.S.; Czech; Engineering; Research; Dislocation

INT 9707863 Beltz This U.S.-Czech engineering research project between Glenn Beltz of the University of California, Santa Barbara, and Anna Marchova of the Czech Institute of Thermomechanics, Prague, will address mechanical failure and atomic scale defect formation. These processes influence the ductile versus brittle nature of structural materials. Such characteristics have significance when considering the performance and reliability of high strength steels and advanced intermetallic alloys, especially when they are subject to adverse conditions such as low temperature or harsh chemical environments. The researchers intend to model this material behavior on macroscopic to atomistic scales. Specifically, efforts will feature examination of: 1) the phenomenon of "brittle" crack growth in pre-existing, apparently mobile, dislocations and 2) the role of nanoscale blunting of a sharp crack spreading through a dislocation-free zone, embedded in a plastically deforming medium. Results are expected to improve our understanding of brittle-to-ductile transition and to yield practical methods for reducing the likelihood of brittle failure of structural metallic alloys. This materials engineering research project fuldills the program objective of advancing scientific knowledge by enabling experts in the United States and Central Europe to combine complementary talents and share research resources in areas of strong mutual interest and competence. ??

INT 9707863 Beltz这个美国-捷克工程研究项目由加州大学圣巴巴拉分校的Glenn Beltz和布拉格捷克热机械研究所的Anna Marchova共同完成，将解决机械故障和原子级缺陷形成问题。这些过程会影响结构材料的延性和脆性。这些特性在考虑高强度钢和先进金属间化合物合金的性能和可靠性时具有重要意义，特别是当它们受到低温或恶劣化学环境等不利条件的影响时。研究人员打算在宏观到原子尺度上对这种材料行为进行建模。具体地说，将重点研究：1)在预先存在的、明显可移动的位错中的“脆性”裂纹扩展现象，以及2)在塑性变形介质中通过无位错区扩展的尖锐裂纹的纳米尺度钝化的作用。这些结果有望提高我们对脆性-延性转变的理解，并为降低结构金属合金脆性失效的可能性提供实用的方法。该材料工程研究项目通过使美国和中欧的专家能够将互补的人才结合在一起，并在共同感兴趣和能力强的领域共享研究资源，实现了促进科学知识的计划目标。?？