Author/Authors :
Wei، نويسنده , , H. and Liang، نويسنده , , J.J. and Sun، نويسنده , , B.Z. and Peng، نويسنده , , P. F. Zheng، نويسنده , , Q. and Sun، نويسنده , , X.F. and Dargusch، نويسنده , , M.S. and Yao، نويسنده , , X.، نويسنده ,
Abstract :
The effect of additions of Cr and Ti on the valence-band structures of NiAl alloys was investigated by a combination of photoelectron spectroscopy and first-principles calculations. The measurement of the ultraviolet photoelectron spectra (UPS) demonstrated that the Ni-d band centroid simultaneously moved towards higher energy by 5.26 eV as Ti and Cr were added. The charge transfer from Ti to Ni made the covalent bonding of the NiAl–Ti alloy become stronger due to the ionicity contribution from the Ni–Ti interactions. The Ni–Cr interactions reduced the directionality of the Ni–Al bonds, resulting in a uniform charge density. This meant that the covalent bonding present in the NiAl–Cr alloy exhibited some metallic bonding characteristics.
Keywords :
based on NiAl , B. Electronic structure of metals and alloys , A. Nickel aluminides , Photoelectron spectrum , E. Ab-initio calculations
