GOALI: Defect Detection Microscopy: Microstructure Design for Formability of Wrought Magnesium Alloys

这项研究项目将建立一个框架，用于设计和制造金属微结构，其中包含较少的损伤敏感特征，并随后改善延展性和成形性。为了在合理的实验时间内检测变形多晶材料中的大量缺陷位，将开发一种使能技术--缺陷检测显微镜(DDM)。关键缺陷区域的结构参数(通过DDM恢复)将与缺陷类型相关，以确定稳健的失效起始参数(FIP)。一旦知道了这些相关性，已经为缺陷不敏感的弹性和塑性属性的微结构敏感设计开发的反向方法将被应用于框架，以改善缺陷敏感属性。这项工作将与通用汽车研究实验室合作进行，重点是改善镁的延展性和成形性，用于制造轻型汽车结构。将轻质材料引入美国汽车业是一项关键的国家目标，将从这项工作中受益匪浅。目前制造镁车身覆盖件的生产方法需要高温处理，这阻碍了镁作为一种可行的轻质合金用于大批量汽车生产。如果该项目的目标得以实现，DDM不仅将为在汽车行业应用低成本、低温度的镁来提高车辆燃油效率开辟道路，而且还将成为研究和开发对美国工业至关重要的更广泛的损伤敏感材料应用(如韧性和疲劳)的使能技术。拟议的跨学科活动还汇集了几个传统领域的专业知识，包括机械工程、制造科学、工程设计、材料科学和应用数学。这将对新兴科学和先进技术领域的技能人力资源开发产生重大影响。

This research project will build a framework for the design and manufacture of metal microstructures containing fewer damage-sensitive features, with subsequent improved ductility and formability. An enabling technology, Defect Detection Microscopy (DDM), will be developed in order to detect large numbers of defect sites in deformed polycrystalline materials in reasonable experimental times. Structure parameters (recovered via DDM) in the regions of critical defects will be correlated with defect type to determine robust Failure Initiation Parameters (FIPs). Once these correlations are known, an inverse approach, already developed for microstructure sensitive design of defect insensitive elastic and plastic properties, will be applied to the framework to improve defect-sensitive properties. This work will be undertaken in collaboration with General Motors Research Laboratory, and will focus on improved ductility and formability of magnesium for the manufacture of lightweight automotive structures. The introduction of lightweight materials into the US auto industry is a key national objective that will benefit significantly from this work. Current production methods for fabricating magnesium autobody panels require high temperature processing, preventing the use of magnesium as a viable lightweight alloy for high-volume automobile production. If the aims of this project are met, DDM will not only open the way for cost effective, low temperature, application of magnesium to improve vehicle fuel efficiency in the auto industry, but will also serve as an enabling technology in the study and development of a much broader range of damage-sensitive material applications (such as toughness and fatigue) critical to US industry in general. The proposed interdisciplinary activity also brings together expertise from several traditional fields including mechanical engineering, manufacturing science, engineering design, materials science, and applied mathematics. This will have a significant impact on the development of skilled human resources in emerging science and advanced technology fields.