Droplet-Based Processing of Quasicrystalline Magnesium Alloys for the Production of High-Performance Particulate, Bulk and Coating Materials

本研究的目的是研究Mg-Zn-Y合金液滴凝固过程中的工艺-结构-性能关系，最终目标是开发一种经过安全验证的高性能镁合金颗粒和块体材料加工技术。该方法是使用受控的毛细管射流破碎来实现用单一尺寸的熔融Mg-Zn-Y液滴进行处理，该液滴足够大（50 mm）以避免传统的基于液滴的镁处理所固有的自燃爆炸，但又足够小（500 mm）以产生有用的快速凝固效果。这种方法是新颖的，因为它提供了唯一的安全和有效的手段来生产快速凝固的Mg-Zn-Y显微组织，利用稳定的准晶Mg 42 Zn 50-Y8相在最大程度上强化。控制液滴凝固微观结构的能力是必不可少的，在本方法中，这是通过开发数值微观结构预测控制模型来实现的。这项研究具有社会重要性，因为它提供了一种独特的方法来处理轻质材料，这是核心制造业，如汽车，航空航天和电子工业，特别是用于生产在室温和高温下需要高比强度的移动部件以及便携式音频视频通信计算机设备的部件。通过这项研究获得的知识，通过演讲和出版物传播，也适用于各种其他有色金属和黑色金属合金，功能梯度材料，金属基复合材料和近净形中间产品。通过提供研究生研究助学金，让代表性不足的群体的本科生参与实践项目，以及组织关于液滴和热材料加工的研讨会和讲习班，加强了学生教育。

The objective of this research is to study the process-structure-property relationship in the solidification of Mg-Zn-Y alloy droplets, with the ultimate goal of developing a safety-proven enabling technology for the processing of high-performance magnesium alloy particulate and bulk materials. The approach is to use controlled capillary jet breakup to enable processing with mono-size molten Mg-Zn-Y droplets large enough (50 mm) to avoid pyrophoric explosions intrinsic to conventional droplet-based magnesium processing, yet small enough (500 mm) to produce useful rapid solidification effects. This approach is novel in that it offers the only safe and effective means to produce rapid-solidification Mg-Zn-Y microstructures that exploit the stable quasicrystalline Mg42Zn50-Y8 phase for strengthening at the maximum level. An ability to control the droplet solidification microstructure is essential, which, in the present approach, is achieved by developing a numerical microstructure-predictive control model.This research bears societal importance as it provides a unique approach to light materials processing which is critically desired in core manufacturing industries such as automotive, aerospace and electronics industries, particularly for the production of moving parts that require high specific-strength at room and elevated temperatures and parts for portable audio-video-communications-computer equipment. The knowledge acquired through this research, disseminated through presentations and publications, also apply to various other non-ferrous and ferrous alloys, functionally graded materials, metal matrix composites and near-net shape intermediate products. Student education is enhanced through providing graduate research assistantships, involving undergraduate students of underrepresented groups in hands-on projects, and organizing seminars and workshops on droplet-based and thermal materials processing.