Ordering in liquid and its heredity impact on phase transformation of Mg-Al-Ca alloys  

作　　者：Jiang You Cheng Wang Shun-Li Shang Yipeng Gao Hong Ju Hong Ning Yi Wang Hui-Yuan Wang Zi-Kui Liu 

机构地区：[1]State Key Laboratory of Automotive Simulation and Control&School of Materials Science and Engineering,Jilin University,Nanling Campus No.5988 enmin Street,Changchun 130025,China [2]International Center of Future Science,Jilin University,Changchun 130012,China [3]Department of Materials Science and Engineering,The Pennsylvania State University,University Park,PA 16802,United States of America

出　　处：《Journal of Magnesium and Alloys》2023年第6期2006-2017,共12页镁合金学报（英文）

基　　金：Financial supports from The National Natural Science Foundation of China(Nos.52074132,51625402,and U19A2084)are greatly acknowledged;financial support came from The Science and Technology Development Program of Jilin Province(Nos.20200401025GX and 20200201002JC);The Central Universities,JLU,Program for JLU Science and Technology Innovative Research Team(JLUSTIRT,2017TD-09);the finacial support from the U.S.Department of Energy via Award number DE-NE0008945。

摘　　要：It is a long-sought goal to achieve desired mechanical properties through tailoring phase formation in alloys,especially for complicated multi-phase alloys.In fact,unveiling nucleation of competitive crystalline phases during solidification hinges on the nature of liquid.Here we employ ab initio molecular dynamics simulations(AIMD)to reveal liquid configuration of the Mg-Al-Ca alloys and explore its effect on the transformation of Ca-containing Laves phase from Al2Ca to Mg_(2)Ca with increasing Ca/Al ratio(rCa/Al).There is structural similarity between liquid and crystalline phase in terms of the local arrangement environment,and the connection schemes of polyhedras.The forming signature of Mg_(2)Ca,as hinted by the topological and chemical short-range order originating from liquid,ascends monotonically with increasing rCa/Al.However,Al_(2)Ca crystal-like order increase at first and then decrease at the crossover of rCa/Al=0.74,corresponding to experimental composition of phase transition from Al_(2)Ca to Mg_(2)Ca.The origin of phase transformation across different compositions lies in the dense packing of atomic configurations and preferential bonding of chemical species in both liquid and solid.The present finding provides a feasible scenario for manipulating phase formation to achieve high performance alloys by tailoring the crystal-like order in liquid.

关 键 词：Liquid alloy SOLIDIFICATION Crystalembryo Short-rangeorder Ab initio molecular dynamics 

分 类 号：TG146.22[一般工业技术—材料科学与工程]