CAREER: Designing Ceramic Microstructures by Controlling Anisotropic Grain Boundary Motion

非技术概述陶瓷材料用于各种高科技应用，从飞机发动机到微处理器。许多陶瓷都是由称为晶粒的微观特征组成的。这些晶粒的大小决定了许多材料的性能，包括抗裂性。制造可靠的陶瓷部件的一个重大挑战是控制晶粒尺寸的能力，因为晶粒在加工所需的高温下不可预测地生长。这项工作的目标是揭示陶瓷材料中晶粒生长的潜在机制，以指导新的加工方法以获得最佳性能。为了实现这一目标，该计划培养下一代陶瓷工程师先进材料加工的必要技能。此外，该计划的教育目标是通过让大学预科艺术学生参与展示艺术和科学过程之间相似性的活动，建立一支具有创造性和多学科的劳动力队伍。为了支持这一努力，一个陶瓷加工套件正在开发和实施K-12 schools.Technical summaryThe目标的职业生涯计划是建立一个机械的方法，利用各向异性晶界运动，以推进微观结构设计。由于晶界重组的流动性的不连续变化已被假设为陶瓷中的不规则晶粒生长的原因。然而，这种重组涉及能量的变化，合并的热力学和动力学的贡献晶界运动。如果没有对晶界运动机制的深入了解，工艺优化依赖于启发式的、低效的测试，这抑制了微观结构设计。该CAREER计划中的实验方法通过测量具有受控驱动力的平坦晶界的移动性来明确地解卷积晶界运动的热力学和动力学贡献：来自施加磁场的能量。这种各向异性的流动性对微观结构演变的影响，阐明通过晶粒生长研究，使用新的，非破坏性的X射线衍射显微镜。有了这种机械洞察力，可以设计一种新的加工框架来修改晶界，以设计具有先进性能的微结构。发展一支有创造力的多学科工作队伍对实施这样一个处理框架至关重要。因此，该计划包括一项教育计划，将艺术和科学方法结合在大学前活动中，包括开发和实施多学科陶瓷工具包，用于在K-12学校分发。此外，工程专业的学生还将接受陶瓷加工和表征技能方面的培训，以促进材料加工。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARYCeramic materials are used in a variety of high-tech applications, spanning from airplane engines to microprocessors. Many ceramics are composed of microscopic features known as grains. The size of these grains dictates many material properties, including crack resistance. A significant challenge to fabricating reliable ceramic parts is the ability to control the grain size, because grains grow unpredictably at the high temperatures needed for processing. The goal of this work is to uncover the underlying mechanism for grain growth in ceramic materials to guide new processing methods for optimal performance. To accomplish this goal, this program trains the next generation of ceramic engineers in the necessary skills for advanced material processing. Additionally, this program’s educational goal is to build a creative and multi-disciplinary workforce by engaging pre-collegiate art students in activities that demonstrate the similarities between artistic and scientific processes. To support this effort, a ceramic-processing kit is being developed and implemented in K-12 schools.TECHNICAL SUMMARYThe goal of this CAREER program is to establish a mechanistic approach that leverages anisotropic grain boundary motion to advance microstructure design. Discontinuous changes in mobility due to grain boundary restructuring have been hypothesized as the cause of irregular grain growth in ceramics. However, this restructuring involves a change in energy, conflating the thermodynamic and kinetic contributions to grain boundary motion. Without this insight into grain boundary motion mechanisms, processing optimization relies on heuristic, inefficient testing, which inhibits microstructure designs. The experimental approach in this CAREER program unambiguously deconvolutes the thermodynamic and kinetic contributions of grain boundary motion by measuring the mobility of flat grain boundaries with a controlled driving force: energy from an applied magnetic field. The impact of this anisotropic mobility on microstructure evolution is elucidated through grain growth studies using new, non-destructive x-ray diffraction microscopy. With this mechanistic-insight, a new processing framework can be designed for modifying grain boundaries to design microstructures with advanced performance. The development of a creative, multi-disciplinary workforce is critical to implementing such a processing-framework. Therefore, this program encompasses an educational plan that combines artistic and scientific methodologies in precollegiate activities, including developing and implementing a multidisciplinary ceramic kit for distribution in K-12 schools. Additionally, engineering students are trained in ceramic processing and characterization skills necessary to advance materials processing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.