Understanding the interplay of precipitates and dislocations on the reversible martensitic transformation in cyclically actuated NiTiHf shape memory alloys

了解循环驱动 NiTiHf 形状记忆合金中析出物和位错对可逆马氏体相变的相互作用

• 批准号: 2004752
• 负责人: Yu Kelvin Xie
• 金额: $ 49.48万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004752&HistoricalAwards=false
• 关键词: Understanding; interplay; precipitates; dislocations; reversible

NON-TECHNICAL SUMMARYShape memory alloys (SMAs) can contract and extend, like an artificial muscle, upon cooling and heating through a process called martensitic transformation. Similar to muscles, shape memory alloys experience fatigue after a number of operation cycles. The fatigue of shape memory alloys is triggered and then exacerbated by the creation and accumulation of ultra-small crystalline defects called dislocations. Recent work has shown that the fatigue life of the SMAs can be dramatically improved by incorporating nano-sized particles. The purpose of this project is to provide fundamental understanding of how these nano-particles influence the fatigue of these SMAs by using advanced and in situ electron microscopy to watch the interactions of the nanoparticles with the defects in real time. These insights will accelerate the development of fatigue-resistant and durable super-elastic SMAs that may beneficially impact a wide variety of critical technologies, including aerospace, energy conversion, biomedical, defense, and transportation. This project will also provide multidisciplinary STEM educational and career advancement opportunities for underrepresented students through the Louis Stokes Alliance for Minority Participation program, as well as online STEM course material based on this research.TECHNICAL SUMMARYThe goal of the project is to develop a fundamental understanding of the interplay between nanoprecipitates, dislocations, and martensitic transformation, during thermo-mechanically induced, reversible martensitic transformation. The new knowledge gained will elucidate how their interactions control fatigue performance (both functional and structural) in cyclically actuated high-temperature shape memory alloys (SMAs). The central hypothesis is that the nanoprecipitates will suppress the transformation-induced dislocation multiplication, glide, and rearrangement during thermal cycling, thus dramatically modifying granular-level microstructure, and consequently the fatigue performance. The experimental tasks to be undertaken include: 1) identify precipitate characteristics, associated elastic strain, and local chemistry, 2) determine the effect of precipitates on the transformation-induced dislocation generation and structure evolution, 3) assess the effect of precipitate-dislocation interactions on the austenite and martensite microstructure evolution and the resultant functional fatigue, and 4) identify the role of precipitate-dislocation interaction on persistent slip band formation and crack initiation and growth (structural fatigue) in cyclically actuated SMAs. The experimental results will be used to develop a detailed description of the cyclic reversible martensitic transformation and fatigue responses in precipitate-bearing SMAs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

形状记忆合金（sma）可以像人造肌肉一样在冷却和加热时通过一种称为马氏体相变的过程收缩和伸展。与肌肉类似，形状记忆合金在多次循环操作后也会出现疲劳。形状记忆合金的疲劳是由称为位错的超小晶体缺陷的产生和积累引发并加剧的。最近的研究表明，加入纳米级颗粒可以显著提高sma的疲劳寿命。该项目的目的是通过使用先进的原位电子显微镜实时观察纳米颗粒与缺陷的相互作用，为这些纳米颗粒如何影响这些sma的疲劳提供基本的理解。这些见解将加速抗疲劳和耐用的超弹性sma的发展，这可能会对各种关键技术产生有益的影响，包括航空航天、能源转换、生物医学、国防和运输。该项目还将通过路易斯·斯托克斯少数民族参与联盟计划，以及基于本研究的在线STEM课程材料，为代表性不足的学生提供多学科STEM教育和职业发展机会。技术概述：该项目的目标是在热机械诱导的可逆马氏体相变过程中，对纳米沉淀物、位错和马氏体相变之间的相互作用有一个基本的了解。所获得的新知识将阐明它们的相互作用如何控制循环驱动高温形状记忆合金（sma）的疲劳性能（功能和结构）。研究的核心假设是，在热循环过程中，纳米沉淀会抑制相变引起的位错增殖、滑动和重排，从而显著改变颗粒级微观组织，从而改善疲劳性能。拟进行的实验任务包括：1)确定析出相的特征、相关的弹性应变和局部化学性质；2)确定析出相对相变诱导的位错产生和组织演变的影响；3)评估析出相-位错相互作用对奥氏体和马氏体组织演变和由此产生的功能疲劳的影响。4)确定沉淀-位错相互作用在循环驱动sma中持续滑移带形成和裂纹萌生与扩展（结构疲劳）中的作用。实验结果将用于详细描述含沉淀sma的循环可逆马氏体相变和疲劳响应。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Effects of microstructure and composition on constitutive response of high temperature shape memory alloys: Micromechanical modeling using 3-D reconstructions with experimental validation

• DOI: 10.1016/j.actamat.2022.117929
• 发表时间: 2022-04-23
• 期刊: ACTA MATERIALIA
• 影响因子: 9.4
• 作者: Joy, Jobin K.;Umale, Tejas;Lagoudas, Dimitris C.
• 通讯作者: Lagoudas, Dimitris C.

Crystallographic variant mapping using precession electron diffraction data

使用进动电子衍射数据进行晶体变体绘图

• DOI: 10.20517/microstructures.2023.17
• 发表时间: 2023
• 期刊: Microstructures
• 作者: H. Hansen, Marcus

A reference-area-free strain mapping method using precession electron diffraction data

使用进动电子衍射数据的无参考区域应变映射方法

• DOI: 10.1016/j.ultramic.2023.113700
• 发表时间: 2023
• 期刊: Ultramicroscopy
• 影响因子: 2.2
• 作者: Zhao, Dexin;Patel, Aniket;Barbosa, Aaron;Hansen, Marcus H.;Wang, Ainiu L.;Dong, Jiaqi;Zhang, Yuwei;Umale, Tejas;Karaman, Ibrahim;Shamberger, Patrick
• 通讯作者: Shamberger, Patrick

Structure and substructure characterization of solution-treated Ni50.3Ti29.7Hf20 high-temperature shape memory alloy

固溶处理Ni50.3Ti29.7Hf20高温形状记忆合金的组织和亚结构表征

• DOI: 10.1016/j.scriptamat.2022.114888
• 发表时间: 2022
• 期刊: Scripta Materialia
• 影响因子: 6
• 作者: Dong, Jiaqi;Umale, Tejas;Young, Benjamin;Karaman, Ibrahim;Xie, Kelvin Y.
• 通讯作者: Xie, Kelvin Y.