Doping effect of Ce on structure and mechanical properties of NiAl intermetallics

• Main Authors: HU Xuelan, LU Ruizhi, WANG Zhilong, LIU Yi, WANG Yaru
• Format: Article
• Language: zho
• Published: Journal of Aeronautical Materials 2020-04-01
• Series: Journal of Aeronautical Materials
• Subjects: nial intermetallics; rare earth element ce; electronic structure; mechanical properties
• Online Access: http://jam.biam.ac.cn/article/doi/10.11868/j.issn.1005-5053.2019.000053
• ISSN: 1005-5053; 1005-5053

Based on the first-principles method of the density functional theory, the study analyzed the influence of rare earth element Ce on the structure and mechanical properties of NiAl intermetallics. The study was needed to use Vienne Ab-inito Simulation Package (VASP). The results show that Ce preferentially occupies the Al site in NiAl by comparing formation energy of Ce occupying the Ni site and Ce occupying the Al site. After Ce occupied the Al site, the NiAl supercell is changed, lattice constant is augmented, and as the concentration of Ce increases, the degree of augment in the lattice constant of NiAl gets larger. By analyzing the figures of charge density and state density, it is found that Ce interacts with adjacent atoms and it exists the orbital hybridization and bonding among them. Furthermore, some physical parameters, such as elastic constants, elastic modulus , etc. , were calculated. The results show that Ce reduces the hardness and weakens the stiffness of NiAl. However, through Pugh’s empirical criterion, it’s found that Ce improves the toughness of NiAl. With increasing the concentration of Ce, the toughness of NiAl is better, but the degree of reduction in the hardness and stiffness is larger.