Experimental Studies of Bonding Related Properties in Binary Intermetallics by Convergent Beam Electron Diffraction

摘要

Accurate Debye-Waller (DW) factors of chemically ordered 0-NiAl (B2, cP2, Pm3m) have been measured at different temperatures using an off-zone axis multi-beam convergent beam electron diffraction (CBED) method. We determined a cross over temperature below which the DW factor of Ni becomes smaller than that of Al of ～90K. Additionally, we measured for the first time DW factors and structure factors of chemically ordered γ_1-FePd (Ll_0, tP2, P4/mmm ) at 120K. We were able to simultaneously determine all four anisotropic DW factors and several low order structure factors using different special off-zone axis multi-beam convergent beam electron diffraction patterns with high precision and accuracy. An electron charge density deformation map was constructed from measured X-ray diffraction structure factors for γ_1-FePd.