摘要
为研究Mg-Sn合金中Al掺杂Mg基体与Mg_(2)Sn相不同取向以及Al元素在界面处的分布位置,基于密度泛函理论计算了Al元素掺杂Mg/Mg_(2)Sn不同指数面的界面黏附功、界面能以及界面掺杂能来寻找较稳定的掺杂位置。采用态密度和晶体轨道重叠布居分析了Al元素掺杂对Mg(0001)/Mg_(2)Sn(022)界面电子特性的影响。结果表明,界面处添加Al元素后只有部分掺杂位置有益于加强Mg/Mg_(2)Sn界面的稳定性。添加Al元素后,Mg(0001)/Mg_(2)Sn(001)界面处Sn端黏附功均高于Mg端,而Mg(0001)/Mg_(2)Sn(111)界面正好相反。Al掺杂后的Mg(0001)/Mg_(2)Sn(022)界面能降低了0.07 eV/nm。添加Al元素后,Mg(0001)/Mg_(2)Sn(022)界面位置Ⅳ比较容易掺杂,该位置处的电子结构分析表明掺杂Al元素后Al的s轨道和Sn的p轨道存在明显交互作用,在界面处Al—Sn键占主导地位。
Mg-Sn alloy is a high temperature-creep resistant magnesium alloy that has potential applications in lightweight automobiles.The addition of Sn to Mg can reduce the overall cost of the alloy as Sn is cheaper than rare earth elements.Sn and Mg form Mg_(2)Sn phase on the grain boundary,and this Mg_(2)Sn phase has an excellent precipitation hardening effect.However,coarsened Mg_(2)Sn phase can reduce the age hardening effect of the alloy.Previous experimental studies have showed that the addition of Al element can considerably improve the age hardening effect of Mg-Sn alloy as it segregated at the interface between the Mg matrix and Mg_(2)Sn phase.However,there is a lack of research on the different orientations of Al-doped Mg matrix and Mg_(2)Sn phase and the distribution position of Al element at the interface.Therefore,in this study,the interface adhesion energy,interface energy,and interface doping energy of Al-doped Mg/Mg_(2)Sn with different index surfaces were calculated based on density functional theory to determine more stable doping positions.The effects of Al doping on the electronic structure of Mg(0001)/Mg_(2)Sn(022)interface were analyzed using the density of states and crystal orbital Hamilton population.The results demonstrate that only a part of the Al-doping positions is beneficial in strengthening the stability of Mg/Mg_(2)Sn interface.After the addition of Al,the adhesion energy of Sn termination at Mg(0001)/Mg_(2)Sn(001)interface is higher than that of Mg termination,but the adhesion energy of Sn termination at Mg(0001)/Mg_(2)Sn(111)interface is lower than that of Mg termination.In addition,the interface energy of Mg(0001)/Mg_(2)Sn(022)interface doped with Al decreased by 0.07 eV/nm compared to that of Mg(0001)/Mg_(2)Sn(022)interface.The addition of Al element to Mg(0001)/Mg_(2)Sn(022)facilitates the doping of a special position,which shows an obvious interaction between the s orbital of Al and the p orbital of Sn after Al doping.Moreover,the Al—Sn bonding is found to be dominant at the inter
作者
王福容
张永梅
柏国宁
郭庆伟
赵宇宏
WANG Furong;ZHANG Yongmei;BAI Guoning;GUO Qingwei;ZHAO Yuhong(School of Semiconductors and Physics,North University of China,Taiyuan 030051,China;School of Materials Science and Engineering,North University of China,Taiyuan 030051,China;Beijing Advanced Innovation Center for Materials Genome Engineering,University of Science and Technology Beijing,Beijing 100083,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第6期812-820,共9页
Acta Metallurgica Sinica
基金
国家自然科学基金项目Nos.52074246,22008224,52275390,52205429和52201146
国防基础科研项目Nos.JCKY20204-08B002和WDZC2022-12
山西省重点研发计划项目No.202102050201011
中央引导地方计划项目Nos.YDZJSX-2022A025和YDZJSX2021A027
