项目名称： 温变条件下金属细丝扭转反常塑性行为实验研究

项目编号： No.11472114

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 何玉明

作者单位： 华中科技大学

项目金额： 108万元

中文摘要： 以研究变温条件下微米级金属细丝反常塑性行为中的尺度效应、塑性恢复现象为目的，在自制的金属丝微扭转实验平台基础上，研制原位温度加载与控制单元。开展可控内部晶粒尺寸的超细金属丝试样的制备工作，以定量研究材料的晶粒尺寸效应与非均匀变形引起的尺度效应的耦合问题。在试样制备方面，将对100微米直径细丝进行热处理获取不同晶粒的原丝，然后通过电解减径制备出直径为8-100微米具有相同晶粒尺寸的细丝，为变温条件下的微米量级金属丝的尺度效应实验研究奠定基础。相关研究在国内外尚未成功开展，具有前瞻性。另外，课题组首次在微尺度金属丝常温下的循环扭转中发现塑性恢复现象，相关成果发表在国际学术期刊《物理评论快报》上，但目前还没有关于变温条件下微尺度材料在循环扭转中的塑性恢复现象的报道。本项目拟在金属丝通电加温的条件下，对金属细丝进行循环扭转实验，分析塑性恢复现象与温度之间的关系，争取获得学术界公认的创新性实验结果。

中文关键词： 微扭转；尺度效应；原位温度控制；反常塑性行为；塑性恢复

英文摘要： In order to study the size effects and plastic recovery of micron-scale metallic wires at elevated temperatures, we plan to develop a new heating and temperature-control element based on the self-developed micro-torsion platform. We aim to study both size effects due to limitations by the grain size and due to nonuniform deformation, and their coupling effect, by preparing the wire samples with different diameter and of prescribed grain size. On the sample preparation, the metallic wires with diameter of 100μm are annealed under given conditions to obtain initial samples of different grain sizes. Afterwards, these samples are further electropolished for different time periods to obtain a series of new samples with diameter ranging from 8 to 100μm, but of the same grain size. These processes lay the foundation for the study of the size-dependent behavior of micron-scale metallic wires at elevated temperatures, which has not been carried out yet. On the other hand, we have found an anomalous plastic recovery in the cyclic torsion of micron-scale metallic wires at room temperature for the first time. The related work has been published in the top international journal Physical Review Letters. However, there have been no reports on the phenomenon of plastic recovery in the cyclic torsion of small-volume materials at elevated temperatures. In this project, we plan to perform the cyclic torsion tests on thin metallic wires which are heated in situ by passing an electrical current, and then analyze the relation between plastic recovery and temperature. This research may achieve the internationally recognized experimental results in this field for the first time.

英文关键词： Micro-torsion;Size effect;In-situ temperature control;Anomalous plasticity;Plastic recovery