铝合金在形变过程中强化相Al2Cu分解机制的像差校正电子显微学研究

项目名称： 铝合金在形变过程中强化相Al2Cu分解机制的像差校正电子显微学研究

项目编号： No.51501195

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 周杨韬

作者单位： 中国科学院金属研究所

项目金额： 20万元

中文摘要： 沉淀强化和弥散强化是用以提高工程合金强度的重要机制，而大量事实表明在合金形变过程中一些强化相会发生分解。强化相的分解会对材料的力学性能与安全服役产生重要影响。目前的一些研究结果显示，具有复杂结构的合金第二相的分解可能与其内部的位错滑移有直接联系，但其机制仍不清楚。本项目拟利用透射电子显微学技术为主要研究手段，对铝合金中的重要强化相Al2Cu由于严重变形造成的局部分解现象开展深入研究。通过像差校正透射电子显微术研究形变Al2Cu中几种滑移系的位错核心结构和位错的运动行为，以期在原子尺度揭示Al2Cu中位错运动对该相结构和成分的调制作用，探索塑性变形过程中相分解的机制和规律。该项目将丰富人们对复杂结构合金相中位错结构和滑移行为的认识，加深对合金塑性变形如何造成强化相分解这一机制的理解，为探索长期处于高载荷条件下的金属结构材料的优化设计提供实验依据和理论基础。

中文关键词： 相分解；位错；铝合金；亚埃尺度；透射电子显微学

英文摘要： Precipitation hardening and dispersion hardening have been widely used in many engineering materials to enhance the strength of alloys. However, as more and more investigations showed, those strengthening phases can be decomposed during plastic deformation, leading to degradation of material properties and reliabilities. Some of the recent researches indicated that the local decomposition results from the motion of the dislocations inside, but the inner mechanism still remains unclear. In this project, transmission electron microscopy will be used to study the deformation-induced decomposition of Al2Cu precipitate in an aluminum alloy. The atomic structures and motion behaviors of the dislocations in various slip systems in Al2Cu will be studied by aberration-corrected (S)TEM, aiming to reveal their influences on the structural and chemical stabilities of the compound, then deduce the mechanisms and roles of decomposition during plastic deformation. The research will not only advance our knowledge about the dislocation in the materials with complex structures, but also deepen the understanding of mechanisms of plastic deformation- induced decomposition of the second phase in an alloy. It would provide the theoretical direction for optimizing mechanical properties of engineering materials served under high loading conditions.

英文关键词： phase decomposition;dislocation;aluminum alloy;sub-angstrom scale;transmission electron microscopy