Design of Transforming Materials

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该奖项的研究目标是开发一种基于科学的设计方法，可以扩展到创造具有上级性能的应力诱导相变材料。这项工作提出了在设计新的转换材料，可能表现出非凡的形状记忆和疲劳性能，并定制滞后与换能器，致动器和传感器的潜在应用知识。所提出的新颖实验和先进的DIC（数字图像相关）技术在宏观和微观尺度上将同时利用具有高分辨率能力的多个透镜来精确地建立相成核和生长的开始以及局部应变。所提出的实验是必要的，以指导理论治疗。实验将提供一个关键的理论检查，考虑正向和反向能量路径，并预测应力滞后的基础上潜在的能量。这项工作将进一步了解新兴的下一代形状记忆材料的机械响应与镍，铁，锰和镓成分。这种方法为设计具有相变可逆性的材料铺平了道路。总的来说，这项工作将为更好地理解导致新形状记忆合金开发的机械响应奠定基础。同时，在铁基合金的情况下，加工和使用期间的转变控制机械响应;预测模型是必不可少的，但缺失。教育影响包括在工程课程中引入一门课程，专门将理论和实验联系起来，解决与相变相关的问题。该计划是将我们的研究成果纳入一个短期课程，在循环变形和疲劳领域每两年提供一次。

This award is funded under the American Recovery and Reinvestment Act of 2009(Public Law 111-5). The research objective of this award is to develop a science-based design methodology that can be extended to create materials undergoing stress-induced phase transformation with superior properties. The work proposes to advance knowledge in design of new transforming materials that potentially exhibit extraordinary shape memory and fatigue properties, and tailored hysteresis with potential applications in transducers, actuators, and sensors. The proposed novel experiments and advanced DIC (digital image correlation) techniques at macro- and micro- scales will simultaneously utilize multiple lenses with high resolution capabilities to establish precisely the onset of phase nucleation and growth, and local strains. The proposed experiments are necessary to guide theoretical treatments. Theexperiments will provide a critical check on theory, which considers forward and reverse energy paths, and the stress hysteresis is predicted based on the underlying energetics. The work will develop further understanding of mechanical response of emerging, next generation shape memory materials with Ni, Fe, Mn and Ga constituents. This methodology paves the way for designing materials with transformation reversibility tailored for specific applications.Overall, the work will lay the foundation for a better understanding of the mechanical response leading to the development of new shape memory alloys. At the same time, in the case of iron- based alloys, the transformation during processing and in-service controls the mechanical response; predictive models are essential but missing. The educational impacts include the introduction of a course in the engineering curriculum that specifically links the theory and experiment addressing the issues associated with phase transformations. The plan is to incorporate the results of our research in a short course that is offered biannually in the areas of cyclic deformation and fatigue.