U.S.-Korea Cooperative Research on the Application of Non-Destructive Techniques to Investigate Cavitation in Superplasticity

该奖项提供资金，允许南加州大学材料科学系的Terence G. Langdon博士与韩国科学技术院（KAIST）物理学教授Ho Chul Kim博士进行为期24个月的研究。非破坏性技术在超塑性空化研究中的应用合作研究项目。他们的研究以前是由NSF资助的。int - 8803709。这些科学家和他们的研究小组成员将继续合作，在南加州大学使用破坏性超塑性测试，在韩国科学技术院使用非破坏性超声波速度和光声光谱（PAS）。他们将(1)在南加州大学使用金相学来验证在韩国科学技术院获得的PAS结果，(2)扩大他们的程序，包括低延伸率，(3)扩大他们的研究范围，包括金属以外的材料。超塑性是指某些金属在高温下拉伸时表现出异常高的无颈伸长率，通常超过1000%。这种现象具有相当大的商业价值，因为它在钣金成形中有许多潜在的应用。超塑性的一个主要问题是内腔的形核和生长。这些空腔可能导致材料成型后性能的显著退化。因此，非破坏性地估计空腔的体积，并使用金相技术验证这些估计是很重要的。合作者是本研究领域备受尊敬的科学家。他们过去的合作对这一领域的文献做出了重大贡献。美国科学家将受益于使用韩国科学技术院（KAIST）提供的无损检测设备，而南加州大学（USC）没有。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。韩国参与该项目得到了韩国科学工程财团（KOSEF）的支持。

This award provides funds to permit Dr. Terence G. Langdon, Department of Materials Science, University of Southern California (USC), to pursue with Dr. Ho Chul Kim, Professor of Physics, Korea Advanced Institute of Science and Technology (KAIST), for 24 months, a program of cooperative research on the application of non- destructive techniques to the investigation of cavitation in superplasticity. Their research formerly was supported under NSF Grant No. INT-8803709. These scientists and members of their research groups will continue their collaboration through the use of destructive superplastic testing, at USC, with non- destructive ultrasonic velocity and photoacoustic spectroscopy (PAS) at KAIST. They will (1) use metallography, at USC to verify PAS results obtained at KAIST, (2) extent their procedures to include lower elongations, and (3) expand their investigations to include materials other than metals. Superplasticity refers to the ability of some metals to exhibit exceptionally high, neck-free elongations, often in excess of 1,000%, when pulled in tension at elevated temperatures. This phenomenon is of considerable commercial interest because of the many potential applications in sheet-metal forming. A major problem in superplasticity is the nucleation and growth of internal cavities. These cavities may lead to a significant degradation of the post-forming properties of the material. It is important, therefore, to estimate the volume of cavities, non-destructively, and to verify these estimates using metallographic techniques. The collaborators are highly respected scientists in the field of this research. Their past collaboration has resulted in significant contributions to the literature of this field. The U.S. scientist will benefit from access to facilities for non-destructive testing, available at KAIST, but not at USC. 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. Korean participation in the project is supported by the Korea Science and Engineering Foundation (KOSEF).