CAREER: Understanding Micromechanisms of Fatigue in Shape Memory Alloys

职业：了解形状记忆合金疲劳的微观机制

• 批准号: 1756393
• 负责人: Samantha Daly
• 金额: $ 18.02万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1756393&HistoricalAwards=false
• 关键词: CAREER; Understanding; Micromechanisms; Fatigue; Shape

The research objective of this Faculty Early Career Development (CAREER) Program award is to investigate the fundamental mechanisms that are responsible for fatigue failure in shape memory alloys (SMAs), with a focus on deformation and phase transformation at the microstructural length scale. Low cycle fatigue, where the SMA undergoes a relatively low number of cycles at high stress amplitudes, and very high cycle fatigue, where the SMA undergoes a very high number of cycles at low stress amplitudes, will be studied. The solid-to-solid phase transformation that enables the unique properties of SMAs will be quantitatively characterized at the grain level, and linked to the mesoscopic response and macroscopic stress-strain behavior of these alloys. The resulting unique, quantitative information on phase transformations will be used to improve the accuracy of lifetime and performance predictions, as well as the optimal design, of these materials. Understanding the links between microstructure and macroscopic behavior is a fundamental challenge in the design and use of materials. SMA components - for example, in military, aerospace, biomedical, and automotive applications - are being increasingly used under fatigue conditions, and a quantitative understanding of the effect of microstructure on their fatigue behavior is critically necessary. This project incorporates a number of educational efforts that are closely tied to the proposed research, including undergraduate summer internships, graduate student enrichment involving a collaborative effort with the Department of Mathematics at the University of Bristol, incorporation of research results into coursework, and dissemination of research findings through a public seminar series and television show.

该学院早期职业发展（CAREER）计划奖的研究目标是研究导致形状记忆合金（SMA）疲劳失效的基本机制，重点是微观结构长度尺度上的变形和相变。将研究低循环疲劳（即 SMA 在高应力幅值下经历相对较少的循环次数）和极高循环疲劳（即 SMA 在低应力幅值下经历非常多的循环次数）。使 SMA 具有独特性能的固-固相变将在晶粒水平上进行定量表征，并与这些合金的细观响应和宏观应力应变行为相关。由此产生的有关相变的独特定量信息将用于提高这些材料的寿命和性能预测以及优化设计的准确性。了解微观结构和宏观行为之间的联系是材料设计和使用的基本挑战。 SMA 部件（例如，在军事、航空航天、生物医学和汽车应用中）在疲劳条件下的使用越来越多，定量了解微观结构对其疲劳行为的影响至关重要。该项目包含了许多与拟议研究密切相关的教育工作，包括本科生暑期实习、与布里斯托大学数学系合作的研究生充实活动、将研究成果纳入课程作业以及通过公共研讨会系列和电视节目传播研究成果。