摘要
Crystal structures of nonstoichiometric La(Ni, Sn)5+x (x = 0.1～0.4) alloys prepared by different methods were investigated by using powder X-ray diffraction and Rietveld refinement analysis. Space group of this type of alloys belongs to P6/mmm, in which Sn only occupies the 3g sites. It has been demonstrated that some of the 1a sites of the nonstoichiometric alloy are replaced by the NiNi dumb-bells which have a strong correlation with the anisotropic thermal parameter B33. The preparation methods have an effect on the number of dumb-bells that can substitute the 1a sites. It was found that the annealed alloys have more NiNi dumb-bells in the structure than the rapid solidified and as-cast alloys have while still keep good crystallinity.
基金
This work was supported by the National Natural Science Foundation of China (50071052) and National Natural Science Key Foundation of China (50131040)
