CAREER: The Mechanics of Fracture in Superelastic Materials

Wendy C.Crone，威斯康星大学麦迪逊分校工程物理系工程力学项目助理教授，形状记忆合金(SMA)构成了一种独特的材料类别，已被证明在生物医学、航空航天、微电子和汽车行业中具有广泛的应用。这些材料的晶体结构可以可逆和可重复地改变，允许材料表现出显著的应力诱导和温度诱导的可恢复变形。它们应用的一个关键障碍是开发可靠的SMA材料和结构，其中材料的微观结构得到了很好的了解，并能够可靠地预测其抗疲劳和断裂性能。本研究要研究的关键问题包括：确定工艺诱导的微观组织对断裂和疲劳行为的影响；探索细化晶粒对微米到纳米尺寸的晶粒断裂行为的影响；以及开发基于实验的模型来描述影响NiTi和铜基SMA断裂和疲劳的机制。结合这项研究，将采取教育举措，在本科生和研究生水平上开展关于超弹性行为和形状记忆材料的广泛培训，通过纳米材料、微观力学和断裂力学领域的新课程材料。扩展的课程材料不仅将向学生介绍力学一直在发展影响并对新技术做出关键贡献的主题，它还将通过世界大学网络的智能材料范例产生国际影响，世界大学网络是一个国际研究人员/教育工作者网络。

CAREER: The Mechanics of Fracture in Superelastic Materials ABSTRACTWendy C. Crone, Assistant ProfessorEngineering Mechanics Program, Department of Engineering PhysicsUniversity of Wisconsin - MadisonShape memory alloys (SMA) constitute a unique class of materials that havealready proven to have wide-ranging applications in the biomedical,aerospace, microelectronics, and automotive industries. These materialshave a crystallographic structure that can change reversibly andreproducibly, allowing the material to display dramatic stress-induced andtemperature-induced recoverable deformations. One key hurdle to their useis the development of reliable SMA materials and structures, in which thematerial's microstructure is well understood and its resistance to fatigueand fracture can be reliably predicted. Critical topics to be investigatedin this research involve: determining the effect of process-inducedmicrostructure on fracture and fatigue behavior; exploring the effect ofgrain refinement on the fracture behavior for grain sizes ranging betweenthe micron and nanometer scale; and developing experimentally-based modelsthat delineate the mechanisms influencing fracture and fatigue in NiTi andCu-based SMAs. In conjunction with this research, education initiativeswill be undertaken to develop widespread training at the undergraduate andgraduate levels in superelastic behavior and shape memory materials, vianew course material in the areas of nanomaterials, micromechanics andfracture mechanics. Not only will the expanded course material providestudents with an introduction to topics where mechanics has been developinginfluence and making critical contributions to new technologies, it willalso have international impact via Smart Materials Exemplar of theWorldwide Universities Network, an international network ofresearchers/educators.