Xiaping Zhong

First principle study of AlX (X=3d,4d,5d elements and Lu) dimer

The ground state equilibrium bond length, harmonic vibrational frequency, and dissociation energy of AlX (X=3d,4d,5d elements and Lu) dimers are investigated by density functional method B3LYP. The present results are in good agreement with the available experimental and other theoretical values except the dissociation energy of AlCr. The present calculations show that the late transition metal can combine strongly with aluminum compared with the former transition metal. The present calculation also indicates that it is more reasonable to replace La with Lu in the Periodic Table and that the bonding strengths of zinc, cadmium, and mercury with aluminum are very weak.

First-principles calculations of elastic constants of DO3-Mg3 RE (RE = Sc, Y, La, Ce, Lu)

The elastic constants of DO3-Mg3 RE (RE = Sc, Y, La, Ce and Lu) have been calculated at T = 0?K by applying the projector augmented wave (PAW) method within the generalized gradient approximation (GGA). The polycrystalline shear modulus, Youngs modulus, Poissons ratio and the anisotropic ratio of DO3-Mg3 RE are also estimated. The density of states and bonding charge densities of DO3-Mg3 Ce and DO3-Mg3 Er are calculated to understand the bonding characteristics of Mg3 RE. The calculated results indicate that the rare earth (RE) additions can improve the elastic modulus of Mg alloys. The predicted elastic constants of DO3-Mg3 RE provide helpful guidance for the design of novel Mg alloys.

The 573 K and 773 K isothermal sections of the phase diagram of the Pr–Ni–Ti ternary system

Abstract The 573 K and 773 K isothermal sections of the phase diagram of the Pr–Ni–Ti ternary system were investigated by X-ray diffraction, differential thermal analysis, optical microscopy and electron microscopy techniques. The 573 K isothermal section was restricted to the Pr-rich and Ti-rich parts of the Pr–Ni–Ti ternary system. The 773 K isothermal section was restricted to the Ni-rich part of the Pr–Ni–Ti ternary system. The (partial) 573 K isothermal section consists of 6 single-phase regions, 9 two-phase regions, and 4 three-phase regions. The (partial) 773 K isothermal section consists of 9 single-phase regions, 15 two-phase regions and 7 three-phase regions. The maximum solid solubilities of Ti in PrNi 2 , PrNi 3 , Pr 2 Ni 7 , PrNi 5 , and Ni are about 2.5 at.% Ti, 1.5 at.% Ti, 1.0 at.% Ti, 2.0 at.% Ti, and 7.5 at.% Ti at 773 K, respectively. The solid solubilities of the other single-phase regions were too small to observe. The existence of any ternary compounds was not observed in the two partial ternary isothermal sections. The decomposition of NiTi was not observed in the Ni–Ti binary system or in the Pr–Ni–Ti ternary system.