Mg-Al-Ca合金中二元Laves相的电子结构和力学性能  

Electronic structure and elastic properties of the binary Laves phase in Mg-Al-Ca alloy

作　　者：余伟阳[1] 张利伟[1,2] 付彭怀[3] 

机构地区：[1]河南理工大学物理化学学院,焦作454000 [2]同济大学波耳固体物理研究所,上海200092 [3]上海交通大学材料科学与技术学院,轻合金精密成型国家工程研究中心,上海200030

出　　处：《原子与分子物理学报》2012年第3期554-564,共11页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(10904032);中国博士后科学基金(20100480629);河南省教育厅自然科学基金(2010B140005);河南理工大学青年骨干教师基金(649144);河南理工大学博士基金(B2009-88)

摘　　要：采用基于密度泛函理论的第一性原理方法,研究了Mg—Al-Ca合金中AB_2型二元Laves相(如CaMg_2,CaAl_2和MgAl_2)在不同形态结构(C14,C15和C36)下的晶体结构、电子结构和力学性能.计算所得的晶格常数与实验数据吻合很好.形成能与相关能的计算表明C15-CaAl_2 Laves相具有很好的合金化能力和结构稳定性.态密度和电荷密度的计算从微观上进一步分析了C15-CaAl_2具有很好的合金化能力和稳定性的根源.弹性常数的计算和力学性能的分析表明C14-MgAAl_2具有很好的延展性,C15-MgAAl_2具有很好的塑性.In this paper, we have carried out first-principles theoretical calculations to investigate the e- lectronic structure and mechanical properties of the ABz type binary Laves phase in Mg-A1-Ca alloy, including C14- C15- and C36- structure for CaMgz, CaAlz and MgA12, respectively. The optimized structural parameters were in very good agreement with the experimental values. The calculated heat of formation and cohesive energy showed that the C15-CaAlz Laves phase was of the strongest alloying a- bility and structural stability. The electronic density of states （DOS） and charge density distribution were given to reveal the micro-mechanism of the good alloying ability and stability of C15-CaAlz. The elastic parameters were calculated and the mechanical properties were analyzed. It was shown that C14- MgAlz is of the best ductility and C15-MgAlz is of the best plasticity in the investigated binary alloys.

关 键 词：Mg-Al-Ca合金 LAVES相 电子结构 力学性能 

分 类 号：O469[理学—凝聚态物理] O481.1[理学—电子物理学]