The crystal structure of Cr2N precipitates in high-nitrogen austenitic stainless steel was investigated by transmission electron microscopy (TEM). Based on the analyses of selected area diffraction (SAD) patterns, the crystal structure of Cr2N was confirmed to be trigonal (P3̄1m) and was characterized by three sets of superlattice reflections: (001), (11/33 0) and (11/33 1). These could be explained in terms of the ε-type occupational ordering of nitrogen. The static concentration waves (SCWs) method was applied to describe the ordered superstructure of Cr2N. The occupation probability function (OPF) for describing the distribution of N atoms in the Cr2N super-structure was derived based on the superlattice reflections obtained in the SAD patterns and could be expressed as: n(r) = c-1/6 η1 cos 2πz + 4/3 η3 cos(2π/3)(x+y+3z). The crystallographic models for ε-type ordering, mainly suggested in the Fe-N system, were discussed in comparison to the present model.
|ジャーナル||Acta Crystallographica Section B: Structural Science|
|出版ステータス||出版済み - 4 1 2005|
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