Indentation-Induced Damage Initiation and Evolution in Single- and Poly-Crystalline Ceramics

单晶和多晶陶瓷中压痕诱发的损伤萌生和演变

• 批准号: 0926798
• 负责人: Yanfei Gao
• 金额: $ 31.5万
• 依托单位: University of Tennessee Knoxville
• 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: 2009-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0926798&HistoricalAwards=false
• 关键词: Indentation; Induced; Damage; Initiation; Evolution

A joint experimental and modeling effort is proposed to study the initiation and growth of crack and the interplay between fracture and plasticity in single- and poly-crystalline ceramics. First, the validity of indentation-cracking method for toughness measurement will be examined, and a parametric map will be constructed to delineate the dependence of the ratio of crack size and contact radius on indenter geometry, applied load, toughness, and hardness. Second, by experimentally examining the behavior of several SiC materials during load and depth sensing spherical indentation tests and comparing it to microstructurally based finite element simulations based on crystal plasticity with coupled intergranular and transgranular microfracture using a cohesive zone approach, a detailed picture of the coupled deformation and micro-fracture processes will be developed from which it will be possible to make predictions about how to tailor a microstructure to optimize its energy absorption. The ability to quantitatively predict the initiation and propagation of fracture and the interaction between fracture and plasticity is a critical step towards a mechanistic understanding of deformation and failure properties, as well as ductility and toughness enhancement methods, of ceramic single crystals and polycrystals. The proposed work will provide an excellent opportunity for the graduate and undergraduate students to participate in an experimental/modeling synergistic research that includes micromechanics modeling and computation, and advanced mechanical testing and microstructural characterization. New educational materials will be developed and disseminated through two graduate level classes. The PIs will participate in the existing programs at their institute (supported by NSF and Department of Energy) for education/outreach activities, which are designed to inspire interests of high school and college students in science and engineering careers, as well as for recruiting students from underrepresented groups.

提出了共同的实验和建模工作，以研究裂纹的起始和生长以及单晶陶瓷和多晶陶瓷中断裂与可塑性之间的相互作用。首先，将检查凹痕裂解方法的有效性，并将构建参数图，以描绘裂纹大小和接触半径对凹痕几何形状，施加载荷，韧性和硬度的比率的依赖性。其次，通过实验检查在负载和深度感测球体压痕测试中的几种SIC材料的行为将开发变形和微裂纹过程，从中可以预测如何量身定制微观结构以优化其能量吸收。定量预测断裂的起始和传播的能力以及断裂与可塑性之间的相互作用是朝着对变形和失效特性的机械理解以及耐陶瓷单晶和多晶的延展性和韧性增强方法的关键步骤。拟议的工作将为研究生和本科生提供一个绝佳的机会，参加包括微力学建模和计算以及先进的机械测试和微观结构表征的实验/建模协同研究。新的教育材料将通过两个研究生级课程开发和传播。 PI将参加其研究所的现有计划（在NSF和能源部的支持下）进行教育/外展活动，该活动旨在激发高中和大学生在科学和工程职业中的利益，以及招募学生来自代表性不足的群体。