NSF-Europe: U.S. - Germany Research Collaboration: "Bridging Length Scales in Deforming Single and Textured Polycrystals of Structural Magnetic Shape Memory Alloys"

该补助金探索从粉末前体和单晶生长制造织构FeNiCoTi和CoNiAl磁性形状记忆合金（MSMA）多晶。一个主要的目标是表征的微观结构，物理和磁热机械（MTM）的行为，更好地理解的机制，负责磁，热和机械诱导的应变在MSMA。沿着实验研究，建模工作将考虑外部磁场和纹理。粉末将通过高压气体雾化制备，通过施加磁场沿易磁化轴取向沿着，并通过温热等通道角挤压（ECAE）和热等静压来固结。沿着应力、温度和磁场下的机械测试，计划使用原位透射电子显微镜和取向成像显微镜进行微观结构表征，并使用量热法和X射线衍射进行物理表征。金属粉末的固结和SMA的建模将在德克萨斯州A M大学进行，而热机械特性将与帕德博恩大学合作进行，该大学在活性粉末的此类活动方面具有丰富的经验。&与传统的SMA（如NiTi）相比，纹理化MSMA多晶的创新处理预计将导致高场致驱动力水平、用于磁激活的所需微观结构形态以及更高的响应频率。拟议的研究将有助于促进当地制造和使用SMA和磁性材料的工程文化。这将不仅是通过教育研究生和本科生直接参与这个项目在与德国学生和研究人员的协作环境，但也通过建立示范和实验室实验到目前的课堂活动。研究人员计划利用拟议的研究来帮助开发一个新的活性材料研究生课程。在得克萨斯州的其他推广和教育活动将用于传播知识获得数学和科学K-12教师和目前的高中学生来自不同背景。& * 该NSF项目由多学科活动办公室、材料研究部（金属研究）和国际办公室（西欧）共同资助，是NSF和欧洲之间的材料研究合作活动（NSF 02 - 135）。该项目正在与德国的帕德博恩大学合作进行。

The grant explores fabrication of textured FeNiCoTi and CoNiAl magnetic shape memory alloy (MSMA) polycrystals from powder precursors and single crystal growth. A major objective is to characterize the microstructural, physical and magneto-thermo-mechanical (MTM) behavior for better understanding of the mechanisms responsible for magnetically, thermally and mechanically induced strains in MSMAs. Along with the experimental studies, modeling effort will take into account the external magnetic field and texturing. The powders will be prepared by high-pressure gas atomization, oriented along the easy magnetization axis by application of a magnetic field and consolidated by warm equal channel angular extrusion (ECAE) and hot isostatic pressing. Along with mechanical testing under stress, temperature as well as magnetic field, microstructural characterization is planned with in-situ transmission electron microscopy and orientation imaging microscopy, and physical characterization with calorimetry and X-Ray diffraction. The consolidation of metallic powders and modeling of SMAs will be performed at Texas A&M University while thermomechanical characterization will be performed in collaboration with the University of Paderborn with extensive experience on such activities on active powders. The innovative processing of the textured MSMA polycrystals are expected to lead to high field-induced actuation force levels, desired microstructural morphology for magnetic activation, and higher response frequencies compared to conventional SMAs such as NiTi.%%%The proposed research will help to foster local culture of fabricating and using SMAs and magnetic materials for engineering. This will come about not only by educating graduate and undergraduate students directly involved in this project in a collaborative environment with German students and researchers but also by building demonstrations and laboratory experiments into current classroom activities. The investigators plan to use the proposed research to aid in the development of a new graduate-level course on active materials. Other outreach and education activities at Texas A&M will be used to disseminate knowledge gained to mathematics and science K-12 instructors and current high school students from diverse backgrounds. ***This NSF project is co-funded by the Office of Multidisciplinary Activities, the Division of Materials Research (Metals Research) and International Office (Western Europe) as a Cooperative Activity in Materials Research between the NSF and Europe (NSF 02-135). This project is being carried out in collaboration with University of Paderborn in Germany.