On July 30th, the research group of Professor Su Yanqing from the State Key Laboratory of Metal Precision Hot Working of Harbin Institute of Technology and Professor Robert Richie of the Lawrence Berkeley National Laboratory "Nanometer-scalegradient atomic packing structure surrounding soft spots in metallic glasses" was published in the well-known journal "Natural Cooperative Journal: Computational Materials" in the field of computational materials science in the field of materials. This paper uses molecular dynamics calculations to reveal the gradient distribution of atomic stacking structures in the soft region in the nanometer range of amorphous alloys. This discovery provides an important theoretical basis for further understanding and design of high strength and toughness amorphous alloys. The first author of the thesis is Wang Binbin, a 2014 Ph.D. student of the School of Materials Science, under the guidance of Professor Su Yanqing and Associate Professor Luo Liangshun. Professor Su Yanqing and Professor Rich are co-corresponding authors of the paper.
"Journal of Natural Cooperation: Computational Materials Science" is an online, fully open-access international academic journal. It mainly publishes first-class research results in the field of computational simulation and design of materials science, with an impact factor of 8.941.
Since the discovery of amorphous alloys (metal glasses), how to find ordered local stacking structures (especially Chinese procedures) in seemingly "disorderly" atomic arrangements has become the key to understanding their macroscopic properties. The study found that nano-scale structural heterogeneity is an intrinsic characteristic of amorphous alloys. There are a large number of soft and hard regions in the alloy. The soft regions have been proven to be the structural origin of amorphous alloy relaxation and plastic deformation. However, due to the lack of knowledge of the procedures in the interior of amorphous alloys, the characteristics of the atomic arrangement in and around the soft region have not been clearly defined, and related theoretical work is full of challenges. This paper takes several different types of amorphous alloys as research objects, and uses a large-scale molecular dynamics calculation method to reveal that a gradient atom stacking structure exists in the nano-scale region in the amorphous alloy. The interior of the amorphous alloy can be specifically divided into three different types of regions: solid-like regions, transition regions, and liquid-like regions. This finding helps to quantitatively compare the number of soft regions in different amorphous alloys, and further understands the deformation behavior of amorphous alloys, and provides important theoretical guidance for the design of high-toughness metallic glass materials.