First-principles study on structural stability of 3d transition metal alloying magnesium hydride  

作　　者：周惦武 彭平 刘金水 陈律 胡艳军 

机构地区：[1]School of Materials Science and Engineering, Hunan University, Changsha 410082, China

出　　处：《中国有色金属学会会刊：英文版》2006年第1期23-32,共10页Transactions of Nonferrous Metals Society of China

基　　金：Project(20020530012) supported by Doctoral Program Foundation of Ministry of Education of China

摘　　要：A first-principles plane-wave pseudopotential method based on the density functional theory was used to investigate the energy and electronic structure of magnesium hydride (MgH2) alloyed by 3d transition metal elements. Through calculations of the negative heat formation of magnesium hydride alloyed by X (X denotes 3d transition metal) element, it is found that when a little X (not including Sc) dissolves into magnesium hydride, the structural stability of alloying systems decreases, which indicates that the dehydrogenation properties of MgH2 can be improved. After comparing the densities of states(DOS) and the charge distribution of MgH2 with or without X alloying, it is found that the improvement for the dehydrogenation properties of MgH2 alloyed by X attributes to the fact that the weakened bonding between magnesium and hydrogen is caused by the stronger interactions between X (not including Cu) and hydrogen. The calculation results of the improvement for the dehydrogenation properties of MgH2-X (X=Ti, V, Mn, Fe, Co, Ni, Cu) systems are in agreement with the experimental results. Hence, the dehydrogenation properties of MgH2 are expected to be improved by addition of Cr, Zn alloying elements.A first-principles plane-wave pseudopotential method based on the density functional theory was used to investigate the energy and electronic structure of magnesium hydride （MgH2） alloyed by 3d transition metal elements. Through calculations of the negative heat formation of magnesium hydride alloyed by X （X denotes 3d transition metal） element, it is found that when a little X （not including Sc） dissolves into magnesium hydride, the structural stability of alloying systems decreases, which indicates that the dehydrogenation properties of MgH2 can be improved. After comparing the densities of states（DOS） and the charge distribution of MgH2 with or without X alloying, it is found that the improvement for the dehydrogenation properties of MgH2 alloyed by X attributes to the fact that the weakened bonding between magnesium and hydrogen is caused by the stronger interactions between X （not including Cu） and hydrogen. The calculation results of the improvement for the dehydrogenation properties of MgH2-X （X=Ti, V, Mn, Fe, Co, Ni, Cu） systems are in agreement with the experimental results. Hence, the dehydrogenation properties of MgH2 are expected to be improved by addition of Cr, Zn alloying elements.

关 键 词：MgH2 镁合金 合金化 结构稳定性 密度功能理论 电子结构 热加工 

分 类 号：TG115[金属学及工艺—物理冶金]