Dislocation Cellular Structures

位错细胞结构

• 批准号: 8703494
• 负责人: David Quesnel
• 金额: $ 28.8万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-05-01 至 1990-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8703494&HistoricalAwards=false
• 关键词: Dislocation; Cellular; Structures

This is a fundamental study of the role of cellular dislocation structures in the deformation and fracture of materials. It is an outgrowth of previous work on the fundamental mechanisms controlling the steady-state response of cellular dislocation structures produced by fatigue. Since dislocation cellular microstructures and their behaviors are archetypical of the inhomogeneous structures and inhomogeneous behaviors that characterize the deformation of many ductile crystalline materials, the scope of this work is broadened to study dislocation cellular microstructures as phenomena. From the theoretical point of view, several issues are addressed, such as internal stress development, the stabilizing forces that lead to a dynamic steady state, the evolution of cell structures from restricted random dislocation activity, the motion of cell walls, the detailed dislocation mechanisms for slip and dynamic recovery and the onset of instabilities that lead to fracture. Experimentally, this project addresses two of what are believed to be the most significant issues related to cell structures that can be settled experimentally, namely the effects of deformation cell structures (or their absence) in fracture toughness and the effects of partial (or recovery) anneals on the behavior of isothermally formed cellular dislocation structures. The former will be very valuable to the fracture community and its ongoing examination of the shielding concept, while the latter will address the contribution of vacancies and internal stresses to the observed mechanical response of fatigued metals.

这是一项关于细胞位错结构在材料变形和断裂中的作用的基础研究。这是对控制疲劳引起的细胞位错结构稳态响应的基本机制的研究成果。由于位错细胞微观结构及其行为是表征许多延性晶体材料变形的非均匀结构和非均匀行为的典型，因此本工作的范围被扩大到将位错细胞微观结构作为现象来研究。从理论的角度，解决了几个问题，如内应力的发展，导致动态稳态的稳定力，细胞结构从有限的随机位错活动的演变，细胞壁的运动，滑移和动态恢复的详细位错机制以及导致断裂的不稳定性的发生。实验上，该项目解决了两个被认为是与细胞结构相关的最重要的问题，即变形细胞结构（或它们的缺失）对断裂韧性的影响，以及部分（或恢复）退火对等温形成的细胞位错结构行为的影响。前者将对断裂界及其正在进行的屏蔽概念的研究非常有价值，而后者将解决空位和内应力对观察到的疲劳金属力学响应的贡献。