CAREER: Interface Deformation and Compatibility in Shape Memory Polycrystals

职业：形状记忆多晶的界面变形和兼容性

• 批准号: 1352524
• 负责人: David Duquette
• 金额: $ 54万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1352524&HistoricalAwards=false
• 关键词: CAREER; Interface; Deformation; Compatibility; Shape

Technical Summary:Shape Memory Alloys (SMAs) are unique multifunctional phase-change materials. They can switch between two shapes under thermal or mechanical cycling by a reversible martensitic phase transformation, and are promising for applications in sensing, actuation, energy conversion and harvesting, and damping. This CAREER project bridges two thus far separate research areas, (i) grain boundary science and engineering and (ii) displacive martensitic transformations in SMAs, and seeks to understand mechanical interactions across interfaces during martensitic transformations in dual-phase SMA polycrystals. This research will use experiments, analytical theory, and mesoscale computational modeling to explore two major interface effects: (1) the effects of grain boundary crystallographic character on strain transfer, accommodation, and compatibility at grain boundaries; (2) how a non-transforming, ductile phase precipitated along grain boundaries accommodates transformation strains from across phase boundaries. Grain boundary engineering will be explored to enhance strain compatibility at grain boundaries, thereby improving the ductility and applicability of SMA polycrystals. The fundamental understanding on strain transfer and compatibility at interfaces gained in this research will also be relevant to similar problems in many other polycrystalline metals and compounds. Non-Technical Summary:Shape Memory Alloys (SMAs)are unique multifunctional materials. They can fail by brittle fracture along internal planar defects or interfaces called grain boundaries and this problem has significantly limited their applicability. This project will quantitatively elucidate the mechanisms for failure in SMAs by performing experimental characterizations and computational modeling. This work will also exploit grain boundary engineering strategies to improve grain boundary properties and enhance the ductility of SMAs, which will enable practical applications of SMAs in advanced technologies in both commercial and military sectors. This project will also involve substantial education and outreach efforts. The education activities include transforming both undergraduate and graduate core mechanical properties courses, contributing to computational materials course, and training undergraduate and graduate researchers who will become experts and leaders in mechanical properties, metals, and computational materials science. The outreach activities will attract young students to science and engineering, promote public interest in engineering, and support professional development and advancement of women engineering students.

形状记忆合金(SMA)是一种独特的多功能相变材料。它们可以通过可逆的马氏体相变在热循环或机械循环下在两种形状之间切换，在传感、驱动、能量转换和收集以及减振方面具有广阔的应用前景。这一职业项目连接了两个迄今为止独立的研究领域，(I)晶界科学和工程以及(Ii)形状记忆合金中的马氏体位移相变，并试图了解双相形状记忆合金多晶中马氏体相变过程中跨界面的机械相互作用。本研究将利用实验、分析理论和介观计算模型来探索两个主要的界面效应：(1)晶界晶体特征对晶界应变传递、调节和相容的影响；(2)沿晶界析出的非相变延性相如何适应来自相界的相变应变。探索晶界工程以提高晶界应变兼容性，从而改善SMA多晶的延展性和适用性。在这项研究中获得的关于应变传递和界面兼容性的基本理解也将与许多其他多晶金属和化合物中的类似问题相关。形状记忆合金(SMA)是一种独特的多功能材料。它们可能会沿着内部平面缺陷或称为晶界的界面脆性断裂而失效，这个问题严重限制了它们的适用性。该项目将通过执行实验表征和计算建模来定量地阐明SMA中的失效机制。这项工作还将开发晶界工程战略，以改善晶界性能和提高SMA的延展性，这将使SMA在商业和军事领域的先进技术中得到实际应用。该项目还将涉及大量的教育和外展工作。教育活动包括转变本科生和研究生的核心机械性能课程，为计算材料课程做出贡献，以及培养本科生和研究生研究人员，他们将成为机械性能、金属和计算材料科学的专家和领导者。外展活动将吸引年轻学生进入理工科，促进公众对工程学的兴趣，并支持女性工程学学生的专业发展和进步。