Fcc结构Ti-Al合金的原子状态及其性质
来源期刊：中南大学学报(自然科学版)2003年第6期
论文作者：余方新 谢佑卿 聂耀庄 陶辉锦 李小波 彭红健
文章页码：598 - 602
关键词：特征晶体模型;特征原子有效电荷;离散变分法;线性Muffin-tin轨道; Ti-Al合金
Key words：characteristic-crystal model; effective-charge; DVM-Xα; LinearMuffin-tin orbital; Ti-Al alloy
摘 要：在特征晶体模型基础上,引入特征原子的有效电荷概念,从第一原理出发利用特征晶体理论对Fcc结构Ti-Al合金系的无序固溶体、TiAl金属间化合物电子结构和晶体性质进行研究.其过程为:首先采用中心原子团簇模型,用密度泛函理论的离散变分方法确定特征原子的有效电荷;然后用密度泛函理论的线性Muffin-tin轨道法研究特征晶体的电子结构和性质;再根据特征晶体理论的叠加原理计算实际合金的性质,得到固溶体的平衡晶格常数、结合能、体弹性模量随成分变化的关系曲线.计算结果表明,金属间化合物TiAl的平均原子体积和结合能与实验数据一致.
Abstract: Based on the first principle and theory of characteristic-crystal, electronic-structure and lattic properties of TiAl alloys were calculated. Firstly, the effective charge of characteristic atomwas evaluated through the approach on the base of density function theory (DVM-Xα) according to the central atom cluster model. Subsequently, the electronic structure and properties of characteristic crystal can be calculated by way of density functional theory (linear Muffin-tin orbital), then the properties of real alloys with the same structure as characteristic crystal were obtained by general Vegard Law. Following this approach, the Fcc-based disordered solution and metallic compound in Ti-Al system were studied. The relationships between properties and composition of disordered solution were obtained; the properties of metallic compound TiAl were evaluated. The calculated results were compared with the experimental ones, and the results show that the calculation of atomic volume and cohesive energy are in agreement with the experimental ones of TiAl metallic compound.
