题 目：Computational study in amorphous alloys
报告人：Dr. Pengfei Guan
时  间：2013年4月10日(星期三)下午3:30
地  点：中心教学楼610
ABSTRACT
Amorphous alloys, or metallic glasses, have disordered atomic structures which bring big challenges to characterize and describe its structures. Due to the special atomic configurations, the metallic glasses present lots of excellent properties, such as the high strength, high elastic limit etc. On the other hand, them also present the obvious shortcomings, such as the limited ductility, due to the well-known shear deformation method. In the past 50 years, thousands of new metallic glasses have been fabricated and investigated, but major mysteries still remain in the behavior of metallic glass at the atomic level, such as the atomic packing, composition-dependence glass forming ability and mechanisms of shear deformation etc.
Here we use the combination of state-of-the-art computational and experimental techniques to explore the atomic structure and the physics of the mechanical response of amorphous alloys. We provide the experimental evidence of short-range order in metallic glasses which consolidates the foundation of current two atomic packing models. We report a hybrid atomic packing scheme comprised of a covalent-bond-mediated “stereochemical” structure and a densely packed icosahedron in multi-component metalloid-metal glassy systems. The results uncover the structural origins of the excellent glass forming ability of Pd-Ni-P system and may help us understand the bulk metallic glass formation of metal-metalloid alloys. Based on the disorder structure model, we also give some new viewpoints for understanding the mechanical response of metallic glasses, such as the coupling between temperature and stress fields in shear deformation and the physics of cavitation behavior. We hope that our research works will contribute to the construction of the bridge between computational world and real world, and finally reach the “Holy Grail”— Computational materials design.
简历：
Dr. Guan majors in computational materials science and he is interested in the exploring of the structure and structure-property correlation of functional materials, especially, metallic glasses and nano-scale materials. He has published more than 20 peer-reviewed papers in well-known journals, such as Nature Materials, Nature Communication, Phys. Rev. Lett., J. Am. Chem. Soc., Phys. Rev. B, Appl. Phys. Lett., and so on. 
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