Structure and Elemental Distributionin Beilby Layer on the Surface of Fe-Cr-Al-La Alloy


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Adanır H. , Kutelia E. R.

I-manager's Journal of Engineering and Technology, cilt.1, ss.61-71, 2006 (Diğer Kurumların Hakemli Dergileri)

  • Cilt numarası: 1
  • Basım Tarihi: 2006
  • Doi Numarası: 10.26634/jfet.1.4.989
  • Dergi Adı: I-manager's Journal of Engineering and Technology
  • Sayfa Sayıları: ss.61-71

Özet

By the methods of Auger-electron spectrometry (AES), scanning electron microscopy (SEM), fast electron diffraction (FED) and wavelength dispersive spectrometry (WDS), were carried out complex investigations on the structure and elemental distribution in Beilby layer formed during mechanical polishing of ground surface of Fe-44% Cr-4% Al-0.3% La alloy. It was established that, Beilby layer formed during mechanical polishing of ground surface of investigated alloy consists of two sub-zones with uniform thicknesses combined with each other organically. The first (outer)zone with thickness of ~250E is truly amorphous layer saturated by oxygen and carbon atoms; and the second, underlying (inner)zone of ~ 350E thickness, also has high concentration of oxygen and carbon, but has nanocrystallite(~20E) structure (in roentgen-amorphous condition). The ratio between thicknesses of the given zones, which componse the Beilby layer, to certain extent depends on the polishing duration and condition of initial surface preceding to mechanical polishing. On the basis of observable peculiarities of the character in thickness changes, of revealed zones, in the dependence of polishing duration and initial surface condition before mechanical polishing, there develop notions on the hierarchical consequence of stages of Beilby layer (and layers under it) formation as a product of combination of processes, of visco-plastic mass-transfer and growth of crystal structure defects, which are accompanied by plastic deformations. The stabile existence at room temperature the superficial layers with truly amorphous and “roentgen-amorphous” condition, which are so nonequilibrium against underlying crystalline structure, is explained by the dissolution of those layers by carbon and oxygen atoms and their interaction with the basic atoms which compose the investigated alloy.