量子论坛第十九讲

报告题目：原子成像技术在材料研究中的应用

报告人：陈江华，湖南大学教授，博导，材料科学与工程学院院长，教育部“长江学者”特聘教授，千人计划特聘专家。

报告时间：3月28日上午10：30

报告地点：量子楼409报告厅

报告摘要：Developments of high-strength aluminum alloys have always faced a difficult problem: owing to their small size, the early-stage strengthening precipitates are difficult to characterize in terms of composition, structure and evolution. Here we employ atomic-resolution transmission electron microscopy (TEM) imaging and first-principles energy calculations to address these problems. Recent years, we have investigated tens of typical high strength aluminum alloys, such as 2xxx (AlCu, AlCuMg and AlCuLiMg), 6xxx (AlMgSi and AlMgSiCu) and 7xxx (AlZnMg and AlZnMgCu) alloys, with different compositions and with varying thermal processes for understanding their property-structure-process correlations. Using aberration-corrected high-resolution TEM (HRTEM) and aberration-corrected scanning TEM (STEM), much of our attention has been paid to revisit the strengthening precipitates in these important alloys and to clarify the controversies left in the past about their precipitation behaviors. Our study demonstrates the followings:

(1) Atomic-resolution imaging in STEM can provide straightforward structure models at the atomic-scale, whereas atomic-resolution imaging in HRTEM with rapid quantitative image simulation analysis can provide the refined structures with high precision beyond the resolution limitation of the microscope. The combination of the two techniques can be more powerful in solving difficult structure problems in materials science.

(2) Most of the early-stage precipitates in aluminum alloys are highly dynamic in both composition and structure. Typically, having their characteristic genetic skeletons to guide their evolution, these dynamic precipitates initiate, mature and grow with thermal aging following characteristic evolution paths. The fine precipitation scenarios revealed in our studies are rather different from previous understandings in the textbooks and literatures published thus far.

报告人简介：陈江华，湖南大学教授，博导，材料科学与工程学院院长，教育部“长江学者”特聘教授，千人计划特聘专家。1983年毕业于中南大学金属物理专业，1986年在中科院金属研究所获硕士学位，1997年在比利时安特卫普大学电子显微镜实验室获博士学位，2006年回国任湖南大学教授。主要研究领域为电子显微学理论与方法研究、铝合金微观结构研究和铝合金热处理工艺研发。回国后，在湖南大学建成了国际先进、有特色的原子成像技术平台。在普通场发射透射电镜的基础上，成功实现出射波函数重构（EWR）原子成像技术和高角环形暗场扫描透射电镜（HAADF-STEM）原子成像技术，成为世界上能够真正掌握软件校正物镜像差的原子成像技术的三个实验室之一。建成了卓有成效的研究团队，在科研和人才培养上取得了有国际影响的成果，近年来在Science, Nature materials, Acta Materialia, Scripta Materialia, Ultramicroscopy, Micron等学术期刊上，发表学术论文累计100余篇，SCI引用3000余次，授权专利8项。承担了科技部973课题、国家自然科学基金重大科研仪器研究项目、国防基础研究课题、高铁材料重大横向课题等3000余万元的科研任务。