Meso-Scale Plasticity and Deformation Processing

细观尺度塑性和变形加工

• 批准号: 0200509
• 负责人: Henry Yang
• 金额: --
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0200509&HistoricalAwards=false
• 关键词: Meso; Scale; Plasticity; Deformation; Processing

Meso-Scale Plasticity and Deformation ProcessingHenry T. Y. Yang, University of California, Santa Barbara, CASrinivasan Chandrasekar, Purdue University, West Lafayette, INA recently 'discovered' phenomenon with important consequences for plastic deformation at the meso-scale (0.1-10 mm) is strain gradient plasticity, which refers to the collective effects of strain gradient on flow behavior of materials. The discovery of strain gradient plasticity has its origins in measurements, which show that materials display strong size effects in their mechanical response when the characteristic length scale associated with non-uniform plastic deformation is small. Two novel techniques are explored for estimating the flow stress-strain curves of metals and alloys in the presence of strain gradients. The first of these involves simulation and measurement of meso-scale indentation to study the variation of hardness with indenter apical angle. A unique aspect of this approach is the use of cone indenters with different apical angles to impose a wide, but controlled, range of strains and strain gradients in a solid. The second technique involves a study of material response in quasi-static, meso-scale machining where strain gradients are even more intense than in indentation. Here, meso-scale machining is a vehicle for estimating the constitutive stress-strain curve. The research is intended to provide fundamental insights into meso-scale plasticity phenomena; develop and validate techniques for estimating meso-scale flow stress data of relevance to deformation processing; and generate detailed stress-strain data for multi-scale modeling of materials processing operations. These should facilitate the development of sustainable materials processing systems that operate at a high level of efficiency, while creating products of enhanced quality.

细观尺度塑性和变形加工。Y. Yang，加州大学，圣巴巴拉，CASrinivasan Alasekar，普渡大学，西拉法叶，INA最近“发现”的现象与重要后果的塑性变形在细观尺度（0.1-10 mm）是应变梯度塑性，这是指集体效应的应变梯度对材料的流动行为。 应变梯度塑性的发现起源于测量，这表明当与非均匀塑性变形相关的特征长度尺度很小时，材料在其机械响应中显示出强烈的尺寸效应。 两种新的技术进行了探讨，估计金属和合金的流变应力-应变曲线存在的应变梯度。 其中第一个涉及模拟和测量的细观压痕研究硬度与压头顶角的变化。 这种方法的一个独特之处是使用具有不同顶角的锥形压头来在固体中施加广泛但受控的应变和应变梯度范围。 第二种技术涉及准静态，细观尺度加工的应变梯度甚至比压痕更强烈的材料响应的研究。 在这里，介观尺度加工是一个车辆估计本构应力-应变曲线。该研究旨在为细观塑性现象提供基本见解;开发和验证用于估计与变形加工相关的细观流动应力数据的技术;并为材料加工操作的多尺度建模生成详细的应力-应变数据。 这将有助于发展可持续的材料加工系统，以高效率运作，同时创造更高质量的产品。