摘要
采用第一性原理方法,对比研究了Zr-Al-C体系纳米层状化合物ZrAl 4C 4、Zr 2Al 4C 5和Zr3Al4C6的结构、弹性和电子性质,并探寻其规律性。结果表明:从晶体结构角度分析,三种材料均可看作由(ZrC)和(Al4C3)两个独立单元以不同比例组合而成,可统一表示为(ZrC)nAl4C3(n=1,2,3),且三者的晶格常数a近似相等,晶格常数c随着ZrC含量的增大而变大。三种化合物弹性性质中,体模量、剪切模量、杨氏模量的大小关系满足:ZrAl4C4<Zr2Al4C5<Zr 3Al4C6。通过对三者电子态密度和Mulliken布局分析得到,ZrAl4C4、Zr 2Al4C5和Zr3Al4C6均具有金属键、离子键和共价键的特征,且Zr—C键强于Al—C键,从微观电子角度解释了在(ZrC)nAl4C3(n=1,2,3)体系中Zr—C键含量越高则对应材料的体模量、剪切模量、杨氏模量等弹性性质越大。计算结果与已有实验值和理论值吻合较好。
The structure,elastic and electronic properties of ZrAl4C4,Zr2Al4C5 and Zr3Al4C6 were explored by first-principles calculations.The results show that these compounds are composed of two independent units(Zr C)and(Al4C3)in different proportions,and these compounds can be expressed as(Zr C)nAl4 C3(n=1,2,3)from the perspective of structural relations.The bulk modulus,shear modulus,and Young’s modulus follow the relationship of ZrAl4C4<Zr2Al4C5<Zr3Al4C6.Through the analysis of the electronic density of states and the Mulliken population,it is found that that the bonding nature of ZrAl4C4,Zr2Al4C5 and Zr3Al4C6 is a combination of covalent,ionic and metallic,and the order of bond strength follows Zr-C>Al-C.In the(Zr C)nAl4C3(n=1,2,3)system,with the larger ratio of the Zr-C bond content,the elastic modulus have the larger values.The calculation results in this paper agree well with the existing experimental and theoretical values.
作者
罗至利
李辉
王磊
刘开平
刘哲
宋佳凡
彭艺杰
LUO Zhi-li;LI Hui;WANG Lei;LIU Kai-ping;LIU Zhe;SONG Jia-fan;PENG Yi-jie(School of Materials Science and Engineering,Chang'an University,Xi'an 710064,China)
出处
《科学技术与工程》
北大核心
2019年第32期99-104,共6页
Science Technology and Engineering
基金
长安大学中央高校基金(300102318202)
长安大学“大学生创新创业训练计划”(201810710120)资助
西北工业大学超高温结构复合材料重点实验室创新基金(6142911010203)