U.S.-Korea Cooperative Research on Properties, Transforma- tion Characteristics and Shape Memory Behavior of Grain Re- fined Copper-Zinc-Aluminum Alloys

该提案要求资金允许伊利诺伊大学冶金学教授C. M. Wayman博士与韩国科学技术院精密金属研究实验室主任Myung-Chul Shin博士进行为期24个月的合作研究项目，研究金属的性质、转变特征、晶粒细化铜锌铝合金的形状记忆行为。这些合金通常是黄铜，按重量计含有约70%的铜和2-8%的铝。它们证明了在较低温度下变形的合金在加热到较高温度时完全恢复其初始未变形形状的形状记忆效应。该研究将涉及应用晶粒细化技术，如锆掺杂，以减少晶粒尺寸，以提高成形性和抗疲劳性。透射电子显微镜和分析电子显微镜将用于检查晶粒内和沿晶界的可能富含锆的第二相颗粒，而颗粒的化学成分将由分析电子显微镜显微分析确定。粒子的相干度、应变场和其他力学方面将用透射电子显微镜来测定。宏观方面的研究将包括合金的晶粒尺寸与疲劳、转变温度和晶粒细化合金的形状记忆程度的表征。这项研究很重要，因为形状记忆合金在控制、紧固件、电子系统、医疗假肢、执行器和其他运输、计算机、机械、农业、能源、建筑和其他制造团体的设备中的应用范围广泛。该项目与美韩合作科学项目的目标相关，该项目旨在通过科学信息、思想、技能和技术的交流以及在互利问题上的合作，提高美韩科学家和工程师之间的合作水平。美国和韩国的合作者是在提案领域拥有丰富的研究经验和成果发表记录的备受尊敬的科学家。

This proposal requests funds to permit Dr. C. M. Wayman, Professor of Metallurgy, University of Illinois, to pursue with Dr. Myung-Chul Shin, Head, Precision Metals Research Laboratory, Korea Advanced Institute of Science and Technology, for a period of 24 months, a program of cooperative research on the properties, transformation characteristics, and shape memory behavior of grain-refined copper-zinc-aluminum alloys. These alloys are typically brasses, containing about 70% copper, by weight, and 2-8% aluminum. They demonstrate the shape memory effect through which an alloy deformed at some lower temperature completely recovers its initial undeformed shape upon heating to a higher temperature. The research will involve the application of grain refinement techniques such as zirconium doping to reduce grain size so as to improve formability and resistance to fatigue. Transmission and analytical electron microscopy will be used to examine presumably zirconium-rich second phase particles within the grains and along grain boundaries, while the chemical composition of the particles will be determined by analytical electron microscopy microanalysis. The degree of coherency, strain fields, and other mechanical aspects of the particles will be determined using transmission electron microscopy. Macroscopic aspects of the research will include characterization of the alloys in terms of grain size versus fatigue, transformation temperatures, and the extent of shape memory in the grain refined alloys. This research is important because of the broad range of interest in the applications of shape memory alloys to controls, fasteners, electronic systems, medical prosthetics, actuators, and other devices for transportation, computers, machinery, agriculture, energy, building, and other manufacturing groups. This project is relevant to the objectives of the U.S.-Korea Cooperative Science Program which seeks to increase the level of cooperation between U.S. and Korean scientists and engineers through the exchange of scientific information, ideas, skills, and techniques and through collaboration on problems of mutual benefit. The U.S. and Korean collaborators are highly respected scientists with extensive research experience and productive publication records in the field of the proposal.