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状材料加工技术。该方法是使用可控的毛细管喷射破碎，使单一尺寸的熔融Mg-Zn-Y液滴加工足够大（50毫米），以避免传统液滴镁加工固有的焦性爆炸，但足够小（500毫米），以产生有用的快速凝固效果。这种方法是新颖的，因为它提供了唯一安全有效的方法来产生快速凝固的Mg-Zn-Y显微组织，利用稳定的准晶Mg42Zn50-Y8相进行最大程度的强化。控制液滴凝固组织的能力是必不可少的，在目前的方法中，这是通过开发一个数值组织预测控制模型来实现的。这项研究具有重要的社会意义，因为它为轻材料加工提供了一种独特的方法，这在汽车、航空航天和电子工业等核心制造业中是非常需要的，特别是在室温和高温下需要高比强度的运动部件的生产以及便携式音频-视频通信-计算机设备的部件。通过本研究获得的知识，通过演讲和出版物传播，也适用于各种其他有色金属和铁合金，功能梯度材料，金属基复合材料和近净形状中间产品。通过提供研究生研究助学金，让代表性不足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.