Dynamic Abnormal Grain Growth and the Production of Single Crystals

技术：将对动态异常晶粒生长（DAGG）和新发现的由DAGG产生的大单晶现象进行实验研究。最近在PI的实验室中发现，DAGG可以在商业纯度的钼片材料中制造出大的单晶。与传统的单晶生长方法相比，初步研究已经在低得多的温度（1300-1500摄氏度）和短得多的时间（分钟）下制造出了几厘米长的Mo单晶。这些初步调查提出了一些重要的基本和技术问题，本调查将设法回答这些问题。主要的技术问题有：1。通过DAGG可以生产单晶的产品形态范围是什么？通过DAGG可以产生单晶形式的什么材料？主要的基本问题是：1。2. DAGG的机制是什么？在DAGG期间，塑性应变如何压倒文献中提到的大多数因素，以限制静态异常晶粒生长（SAGG）？商业纯度Mo片的单晶生产已经被证明，这些研究将研究其他产品形式的单晶形成，特别是棒和连续线长度。DAGG在Mo以外的材料中形成单晶的能力也将被研究，特别是在W和Fe-3%Si中。非技术：研究将通过提高对DAGG和一般异常晶粒生长过程的理解来影响冶金领域。新的单晶生产技术，特别是用于难熔金属的单晶生产技术，可能会彻底改变工艺炉行业，并有可能取代许多行业（如白炽灯泡）使用的W和Mo线材料。随后应用于其他材料有望产生额外的影响和效益。除了现有的伙伴关系外，还将寻求与工业界和国家实验室建立新的伙伴关系，以推进这项技术，并更好地培训参与拟议研究的学生。调查将整合研究、培训和教育，包括研究生和本科生的实验室研究，以及在PI下的直接培训和指导。将特别强调对本科生的培训和指导，以及从工程领域代表性不足的群体中招募学生以纳入该项目。建议的研究结果将用于本科和研究生课程的教学材料。拟议项目将加强和支持一所当地小学的外展方案；这个拓展项目是由一个荣誉协会组织的，PI是该协会的指导老师。该项目将支持该机构继续维护和开发独特的高温机械测试设备。所有研究成果将通过同行评议期刊的出版物和在国家和国际专业会议上的演讲来传播；研究生和本科生都将参与研究成果的传播，作为他们培训的一部分。拟议调查的社会影响将包括教学和培训学生以及创造一种全新的有用技术。

TECHNICAL: An experimental investigation will be conducted into dynamic abnormal grain growth (DAGG) and the newly-discovered phenomenon of large single crystal creation by DAGG. It was recently discovered in the PI's laboratory that DAGG can create large single crystals in commercial-purity Mo sheet materials. Preliminary investigations have created Mo single crystals several centimeters in length at far lower temperatures (1300-1500 C) and in much shorter times (minutes) than is possible by conventional single crystal growth methods. These preliminary investigations have raised a number of important fundamental and technological questions which this investigation will seek to answer. Chief among the technological questions are: 1. What ranges of product forms can be produced as single crystals through DAGG, and 2. What materials can be produced in single-crystal form through DAGG? Chief among the fundamental questions are: 1. What is the mechanism of DAGG, and 2. How does plastic straining during DAGG overwhelm most of the factors noted in the literature to limit static abnormal grain growth (SAGG)? Single-crystal production in commercial-purity Mo sheet has been demonstrated, and these investigations will study single-crystal formation in other product forms, notably rod and continuous wire lengths. The ability of DAGG to form single crystals in materials other than Mo will also be investigated, particularly in W and Fe-3%Si. NON-TECHNICAL: Research will impact the field of metallurgy by producing an improved understanding of DAGG and of abnormal grain growth processes in general. The new single-crystal production technologies to be created, particularly for application to refractory metals, is likely to revolutionize the process furnace industry and could potentially replace the W and Mo wire materials used across numerous industries, such as in incandescent light bulbs. Subsequent application to other materials is expected to produce additional impacts and benefits. In addition to existing partnerships, new partnerships will be sought with industry and national laboratories to advance this technology and to better train students participating in the proposed research. The investigations will integrate research, training, and education by including graduate students and undergraduate students in laboratory research and direct training and mentoring under the PI. Particular emphasis will be placed on training and mentoring of undergraduate students and on the recruiting of students from groups underrepresented in engineering for inclusion in the project. Results of the proposed research will be used for instructional materials in both undergraduate and graduate courses. An outreach program to a local elementary school will be enhanced and supported under the proposed project; this outreach program is organized by an honors society for which the PI is faculty adviser. The project will support the continued maintenance and development of unique high temperature mechanical testing facilities at the proposing institution. All research results will be disseminated through publications in peer-assessed journals and presentations at national and international professional meetings; both graduate and undergraduate students will be involved in the dissemination of research results as a part of their training. Societal impacts of the proposed investigation will include teaching and training of students and the creation of a completely new and useful technology.