温度对面心立方金属材料弹塑性转变尺寸效应影响的原位力学行为的研究

This project is to study the temperature influence on the size effect of the elastic-plastic transformation of FCC single crystal metal nanomaterials (such as Cu、Au、Al、Ni) through a serie of in-situ SEM/TEM deformation methods developed by the project applicant, it can reveal the failure mechanism of the metalic nanowires in electron devices which can do great favour to the design of new devices. As our previous study at room temperature, we find, the elastic strain limit will increase with size decreasing and the elastic strain limit of metal had been measured in experimetal at the first time. Plastic deformation mechanism transformed from full dislocations dominated to partial dislocations (including stacking faults and deforamtion twins) dominated, and for the first time the contribution have been quantificated. This project will be focus on the temperature influence on the mechanical response of such nanomaterials,it is a critical item to reveal the failure mechanism of electron device in which metal nanowires are the bascal interconnection lines.Taken several typical FCC metal nanomaterials as our typical examples, reveal their size effect on the elastic-plastic transfomation under different temperature will give basic experimeal data to the metal materials under thermol field, which will offer great help to the design and development of new device.

本项目通过发展的基于扫描电镜和透射电镜的纳米材料原位变形方法研究温度对面心立方金属（Cu、Au、Al、Ni等）弹塑性转变尺寸效应的影响，达到揭示当前电子器件中纳米材料因工作发热导致的失效机理的目的，为今后设计和开发新型电子器件提供第一手的实验和理论数据。利用申请人发展的纳米材料原位变形技术，申请人发现，在室温下，随着尺寸的减小，金属铜纳米材料的弹性应变极限增大，并首次在实验上证实了金属材料理论弹性极限的存在。塑性变形机制也从全位错引导的塑性变形转变为以层错，变形孪晶为主导的塑性变形行为，并定量了各种塑性变形机制对总形变的贡献。针对当前电子器件中纳米材料工作时发热导致的失效问题，本项目将关注温度对作为金属互联线的金属材料力学行为的影响机制，发展原位力、热耦合下原位变形方法揭示几种FCC金属在不同温度区间内的弹塑性变形行为的尺寸效应，为揭示金属材料在热场作用下的力学行为提供基础性的实验数据。

2014-2016年，在本项目的支持下，我们在实验平台、方法和具体科学问题的研究方面都有比较大的进展，具体表现如下：在实验平台发展上，发明了多种透射电镜下用于微纳尺度材料原位变形的实验方法并成功的将温度场、力场、电场引入，形成了几种全新的电子显微镜用材料力、热、电场耦合原位变形方法，并获得了国家专利的授权；在科学研究方面，在透射电镜中采用所发展的方法，对材料在不同环境下（耦合了力场、热场、气场）的服役行为，从原子尺度原位揭示了材料的几种特殊的变形行为，对单体纳米材料在不同外场下的结构演变与性能之间的相关性研究进行了探索，相关结果发表在Nature communications, Nano Letter, Small，Appl. Phys. Lett. 等国际著名期刊上；基于对小尺度材料服役行为的理解，尝试制备了新型纳米基复合材料，实现了集耐高温，阻燃，优异力学性能于一体，相关结果发表在ACS Appl. Mater. Interfaces，Journal of Materials Chemistry A上。