title: Crystallization pathways of liquid-bcc transition for a model iron by fast quenching.
abstract: We report simulations on the local structural evolution in the liquid-bcc transition of a model iron. Fourteen main Voronoi polyhedra are chosen as the representatives of short-range orders (SROs) and their transformations during crystallization are also investigated. Thus, the crystallization pathways for the main SROs are drawn. Our results also show that the transformations between two SROs in the crystallization pathways can be classified into two categories, first the enlargement of coordination number, second the transformation of local symmetry from five-fold to four-fold. The former reduces the potential energy while the latter increases it. It is found that the potential energy cannot decease monotonously whatever crystallization pathway is chosen to transform the icosahedral SRO to bcc SRO. Therefore, the latter transformation might provide the energy barrier of crystallization. We propose two transformation styles among SROs. All the transformations in the crystallization pathways can be achieved according to the styles. Moreover, the two transformation styles indicates that the bcc structure is more similar to liquid than other crystals. That might be the reason why the first phase nucleated during a rapid cooling process should be bcc crystal.
authors.affiliation: College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.|Shanxi key laboratory of advanced magnesium-based materials, Taiyuan University of Technology, Taiyuan, 030024, China.
authors.forename: Shao-Peng
authors.initials: SP
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China.
authors.forename: Shi-Dong
authors.initials: SD
authors.lastname: Feng
authors.affiliation: College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.|Shanxi key laboratory of advanced magnesium-based materials, Taiyuan University of Technology, Taiyuan, 030024, China.
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Qiao
authors.affiliation: Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Wang
authors.affiliation: Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China.
authors.forename: Jing-Yu
authors.initials: JY
authors.lastname: Qin