Study of the iron-nitrogen phases by electron microdiffraction and convergent beam electron diffraction

Abstract

Abstract. 2014 It is shown how electron microdiffraction connected with convergent beam electron diffraction can be used to identify unambiguously the space group of the 03B3,03B3' and 03B5 iron nitrides.The method involves the identification, from microdiffraction patterns, of a partial extinction symbol in agreement with a few possible space groups. The actual space group is then identified by means of the Tanaka "multibeam" method or from observation of the intensity of the diffracted beams on microdiffraction patterns. It is explained how to overcome the experimental difficulties connected with the small crystal size, the texture of the specimen and the absence of HOLZ reflections on most diffraction patterns.

Ball milling induced interstitial atoms redistributions revealed by Mössbauer effect in Fe based alloys

“…Only very sophisticated deconvolutions of carefully obtained diffractograms are likely to avoid ambiguous interpretations. In the case of FeN x this deconvolution achieved by Aufrecht et al [6] has proven that for x ≤ 0.14 the martensitic-like tetragonal structure which had be proposed [9] does not satisfy all the experimental diffraction data and that the α superferritic BCC suggested by Mössbauer spectroscopy [10] and electron diffraction is more realistic [11]. Arguments in favour of α -like structure were also provided by 200 • C ageing of the BM products which in contrast with similar thermal treatment of as-quenched α martensite refused any evidence of α Fe 16 N 2 ordering [12].…”