CAREER: Mechanics of Ultra-Strength Nanomaterials: Revealing Deformation Mechanisms

职业：超强纳米材料力学：揭示变形机制

• 批准号: 1056293
• 负责人: Daniel Gianola
• 金额: $ 60万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1056293&HistoricalAwards=false
• 关键词: CAREER; Mechanics; Ultra; Strength; Nanomaterials

TECHNICAL SUMMARY: This CAREER award supports a research project to characterize a new class of materials, the ULTRA-STRENGTH, which have the capability of withstanding specimen-wide mechanical stresses that approach the theoretical limit, i.e. the maximum achievable stress in crystalline materials. This project is an experimental study to reveal the fundamental deformation mechanisms of ultra-strength nanoscaled materials. Experiments on "hard" materials (metals, ceramics, semiconductors) will attempt to ascertain both the strength- and rate-controlling plasticity mechanisms. The project will employ a suite of quantitative in situ nanomechanical experiments to provide essential links between directly observed structures, defect nucleation and evolution, length scales, and attendant materials response. Systematically varying the testing temperature and employing transient mechanical tests (e.g. strain-rate changes, stress relaxations) will quantitatively elucidate the energy barriers for plastic deformation. This research is driven by three technical objectives: (a) synthesize quasi-defect free single crystalline and heterostructure nanomaterials, (b) employ quantitative in situ nanomechanical testing in high-resolution electron and focused-ion-beam microscopes utilizing varied temperature and transient experiments to identify and study deformation mechanisms at stresses near the ideal limit, and (c) leverage the insight gained of the influence of flaws and defects on attendant mechanical response to engineer novel nanomaterials with microstructural control allowing for hybrid functionality.NON-TECHNICAL SUMMARY: This research project is motivated by several technologically relevant questions: (1) How do nanomaterials accommodate deformation when an entire specimen, feature, or device is subjected to stresses at or near the theoretical limit of strength? (2) How can the strength- and rate-controlling deformation mechanisms of these ultra-strength materials be experimentally elucidated via nanoscale synthesis and quantitative in situ mechanical testing? (3) Can the high dynamic range of elastic strain available in ultra-strength materials be used to tune functional properties such as electrical and thermal transport via strain engineering? The proposed activity aims to enrich the educational and research experience of students at UPenn through new training and outreach programs. The project will include the development of an undergraduate curriculum with infusions of nanoscale materials science & engineering. Additionally, a pilot series of Congressional visits to Washington DC will be launched. It is intended for undergraduates and graduates with hybrid engineering and economics training via the Jerome Fisher Management & Technology Program. Experiences and opportunities will also be provided through the proposed integration of international collaborative research with this project.

技术概要：该CAREER奖项支持一个研究项目，以表征一类新材料，ULTRA-STRENGTH，它具有承受接近理论极限的全尺寸机械应力的能力，即晶体材料中可达到的最大应力。本计画是一项揭示超强度奈米材料基本变形机制的实验研究。对“硬”材料（金属，陶瓷，半导体）的实验将试图确定强度和速率控制塑性机制。该项目将采用一套定量原位纳米力学实验，以提供直接观察到的结构，缺陷成核和演变，长度尺度和伴随的材料响应之间的重要联系。 系统地改变测试温度和采用瞬态力学测试（例如应变率变化，应力松弛）将定量地阐明塑性变形的能量障碍。这项研究由三个技术目标驱动：（a）合成准无缺陷单晶和异质结构纳米材料，（B）在高分辨率电子和聚焦离子束显微镜中采用定量原位纳米力学测试，利用变化的温度和瞬态实验来识别和研究在接近理想极限的应力下的变形机制，以及（c）利用所获得的关于缺陷和缺陷对伴随的机械响应的影响的洞察力来设计具有允许混合功能的微结构控制的新型纳米材料。非技术性概述：本研究项目的动机是几个技术相关的问题：（1）当整个样品、特征或器件受到理论强度极限或接近理论强度极限的应力时，纳米材料如何适应变形？(2)如何通过纳米级合成和定量原位力学测试来实验阐明这些超强度材料的强度和速率控制变形机制？(3)超强度材料中弹性应变的高动态范围是否可用于通过应变工程调整功能特性，如电和热传输？拟议的活动旨在通过新的培训和推广计划丰富宾夕法尼亚大学学生的教育和研究经验。该项目将包括与纳米材料科学工程注入本科课程的发展。此外，还将启动一系列国会议员访问华盛顿的试点活动。它的目的是为本科生和研究生与混合工程和经济学培训通过杰罗姆费舍尔管理技术计划。还将通过拟议的将国际合作研究与本项目相结合的方式提供经验和机会。