Some Studies on Microtexture and Acoustoelasticity in Polycrystalline Media

多晶介质微观结构和声弹性的一些研究

• 批准号: 0103979
• 负责人: Chi-Sing Man
• 金额: $ 15.12万
• 依托单位: University of Kentucky
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-15 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0103979&HistoricalAwards=false
• 关键词: Some; Studies; Microtexture; Acoustoelasticity; Polycrystalline

DMS Award AbstractAward #: 0103979PI: Man, Chi-Sing Institution: University of KentuckyProgram: Applied MathematicsProgram Manager: Catherine MavriplisTitle: Some Studies on Microtexture and Acoustoelasticity in Polycrystalline MediaTo the naked eye, the polished surface of a metal sheet appears as a homogeneous continuum. Under the metallographer's microscope the same surface reveals, after etching, an underlying polycrystalline structure. Many materials, including metals, ice and rocks, are aggregates of tinycrystals or grains, which assume different orientations in space and are separated by interfaces called grain boundaries. Comprehensive mapping of grain boundaries and individual grain orientations in polycrystals has recently become possible with the emergence of orientation imaging microscopy. Details about grain orientations, e.g., the misorientations of neighboring grains, are called microtexture. Microtexture could exert a strong influence on the mechanical behavior of polycrystalline materials (e.g., on the volume of backscattered ultrasonic noise, whichat sufficiently high levels renders ultrasound totally useless for material flaw detection in aircraft engines; an undetected metallurgical defect in the No. 2 engine was the culprit for the crash of a United Airlines DC-10 in 1989).The main objectives of the present project are as follows: (i) to reexamine the mathematical foundations and properties of several theoretical constructs which have been proposed by material scientists for describing microtexture in various degrees of detail and sophistication; (ii) to delineate the effects of microtexture on the mechanical anisotropy of sheet metals in forming operations; (iii) to study the effects of microtexture on the acoustoelastic behavior of stressed polycrystals; (iv) to develop further an earlier study that concerns using the dispersion of Rayleigh waves for the nondestructive inspection of surface layer of residual stress, which is imparted on critical components of aircraft engines to enhance their high-cycle fatigue performance.Date: May 18, 2001

DMS奖Abstractaward＃：0103979PI：货币 - 圣经机构：肯塔基大学计划：应用数学计划经理：Catherine Mavriplistitle：关于微晶和大声弹性的一些研究，在多晶中介体中，多晶介导的多晶型媒介物是北眼的表面，是一个金属片，像家用的金属表面一样，是家的效果。在蚀刻后，相同的表面揭示了基础材料的显微镜，在蚀刻了一种潜在的多晶结构之后。许多材料，包括金属，冰和岩石，都是微小晶体或谷物的聚集体，它们在空间中采用不同的方向，并通过称为晶界的接口分离。随着方向成像显微镜的出现，最近有可能将晶界和各个晶粒取向的全面映射。有关晶粒方向的详细信息，例如，相邻谷物的不良方向称为微纹理。 Microtexture could exert a strong influence on the mechanical behavior of polycrystalline materials (e.g., on the volume of backscattered ultrasonic noise, whichat sufficiently high levels renders ultrasound totally useless for material flaw detection in aircraft engines; an undetected metallurgical defect in the No. 2 engine was the culprit for the crash of a United Airlines DC-10 in 1989).The main objectives of the present project are如下所示：（i）重新审查几种理论构造的数学基础和特性，这些理论构造已由物质科学家提出，用于以各种细节和复杂性描述微XT; （ii）描绘微纹状体对形成操作中纸质金属机械各向异性的影响； （iii）研究微作用对压力多晶的大声弹性行为的影响； （iv）进一步进行了一项较早的研究，该研究涉及使用雷利波的分散体，以对残留应力的表面层进行无损检查，该研究是在飞机发动机的关键组件上施加的，以增强其高循环疲劳性能。