Jin-Chun Li

THEORETICAL STUDY OF PHASE FORMING, MAGNETIZATION AND LATTICE VIBRATIONS OF Fe23-xTxB6(T = Cr, Mn, Ni, C), Fe23 C6, Fe23B6 AND Fe23CB6

We present a theoretical investigation on the phase stability, site preference and lattice constants of Fe23-xTx B6(T = Cr, Mn, Ni, C), Fe23C6 and Fe23CB6. The calculated results show that in Fe23-xTxB6 the Cr, Mn or Ni atoms prefer 4a sites. Fe23CB6 may form with Cr23C6 prototype structure, and the carbon atoms are positioned at 4a sites. The calculated lattice constants are found to agree with report in literatures. We have calculated the magnetic moments of Fe23C6, Fe23B6 and Fe23CB6 compounds. Furthermore, the total and partial phonon densities of states are evaluated first for these compounds. The analysis of the inverted potentials explains qualitatively the contributions of different atoms to the vibrational modes.

Theoretical Study of the Phase Stability, Site Preference, and Lattice Vibration for Fe7-xTxC3 (T=Cr, Mn)

The phase stability and site preference of T (T=Cr, Mn) in Fe7-xTxC3 have been studied based on the pair potentials obtained by the lattice inversion method. The results show that T (T=Cr, Mn) atoms substitute for Fe with a strong preference for the 6c1 sites and the order of site preference is 6c1, 6c2, and 2b. The calculated lattice parameters and magnetic properties are in good agreement with the experimental data. Moreover, the total and partial phonon densities of states and the phonon dispersion curves are evaluated for the first time for the Fe6TC3 (T=Cr, Mn) compounds with the hexagonal structure. The properties related to lattice vibration, such as the phonon density of states, phonon dispersion curves, specific heat, vibrational entropy, and Debye temperatures are also evaluated.

Atomic study of fracture progress of Fe[110]/TMC[100] (TM = Ti, Zr and Hf) semi-coherent interfaces

Using first-principle calculation in combination with the Chen–Mobius inversion method, we get the interfacial potentials of the Fe[110]/TMC[100] (TM = Ti, Zr and Hf) interface system. Based on the interfacial potentials, we investigate the interfacial stability, misfit dislocations and tensile fracture of the semi-coherent interfaces of Fe[110]/TMC[100] (TM = Ti, Zr and Hf). The different sizes of the misfit dislocation models are employed to compare the interfacial energy. Results indicate that Fe[110]/HfC[100] interface is more stable than Fe[110]/TMC[100] (TM = Ti and Zr). The analysis of different tensile fracture processes shows that the misfit dislocations play an important role in the fractures of interfaces between iron and transitional metal carbides.