Ignition-proof mechanism of magnesium alloy added with rare earth La from first-principle study  

作　　者：张国英 罗志成 张辉 褚冉 

机构地区：[1]College of Physical Science and Technoloy,Shenyang Normal University

出　　处：《Journal of Rare Earths》2012年第6期573-578,共6页稀土学报（英文版）

基　　金：National Natural Science Foundation of China(50671069);Natural Science Foundation of Liaoning Province(20102173);the Experimental Central Director’s Foundation of Shenyang Normal University(Sy201103)

摘　　要：The surface segregation of La and its effect on the oxygen adsorption on a Mg （0001） surface for a coverage 0=-0.25 monolayer were performed by using first-principles calculations. The calculated results showed that La atoms preferred occupying surface sites to the bulk sites, which suggested the La surface segregation. When oxygen atoms adsorbed on a pure or La alloyed Mg （0001） surface, certain amount of heat would release, and La alloying made the heat released less, which might increase the ignition point of Mg alloy. Both Mg and La had strong atomic affinity with oxygen, so the oxidation film of Mg-La alloys consisted of MgO, La2O3. The denser La2O3 turned oxide film into free and close structure, and prevented oxygen from passing through the oxidation film. The La-O covalent bonding could explain why La2O3 was compact, and resulted in good ignition-proof of Mg-La alloys.The surface segregation of La and its effect on the oxygen adsorption on a Mg （0001） surface for a coverage 0=-0.25 monolayer were performed by using first-principles calculations. The calculated results showed that La atoms preferred occupying surface sites to the bulk sites, which suggested the La surface segregation. When oxygen atoms adsorbed on a pure or La alloyed Mg （0001） surface, certain amount of heat would release, and La alloying made the heat released less, which might increase the ignition point of Mg alloy. Both Mg and La had strong atomic affinity with oxygen, so the oxidation film of Mg-La alloys consisted of MgO, La2O3. The denser La2O3 turned oxide film into free and close structure, and prevented oxygen from passing through the oxidation film. The La-O covalent bonding could explain why La2O3 was compact, and resulted in good ignition-proof of Mg-La alloys.

关 键 词：magnesium alloys first-principle calculations rare earths surface segregation ignition-proof 

分 类 号：TG146.22[一般工业技术—材料科学与工程]