J.Q. He

First-principles Study of NiAl Alloyed with Rare Earth Element Ce

The structural, elastic, and electronic properties of NiAl alloyed with rare earth element (REE) Ce have been investigated by using density functional theory (DFT). It is found that Ce has a strong AI site preference and causes lattice distortion of NiAl. The calculation of elastic constants shows that Ce increased both the hardness and the ductility of NiAl, which could be explained by the formation of new ionic bonds between AI (and Ni) and Ce and the enhancement of covalent bonds in Ni 8 Al 7 Ce. Our results are in good agreement with the available experimental data and other theoretical results.

The influence of (510) step surface on the segregation of (110)surface of O/Rh x Pt 1−x alloy system

The atomic cluster models of (110) surface of Rh<inf>x</inf>Pt<inf>1−x</inf> disordered binary alloy were constructed under the condition of O adsorption or not, and the coverage rate of O is 0.5. Also the (510)^[1] step surface were constructed on each model. The environment sensitive inlaid energy (E<inf>ESE</inf>) and the electronic structure of the (510) step surface of O/Rh<inf>x</inf>Pt<inf>1−x</inf> system were calculated by Recursion method. The results of E<inf>ESE</inf> show that, the exists of (510) step surface increases the segregation of Rh on the surface of Rh-Pt. The electronic structure shows that in the case of O adsorption, the two peaks in the total density states on the alloy surface is more obvious because of the step stage which also decreased the total density states on the alloy surface.