Pack-boriding of Fe-Mn binary alloys: Characterization and kinetics of the boride layers


BEKTES M., CALIK A. , UÇAR N. , KEDDAM M.

MATERIALS CHARACTERIZATION, vol.61, no.2, pp.233-239, 2010 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 61 Issue: 2
  • Publication Date: 2010
  • Doi Number: 10.1016/j.matchar.2009.12.005
  • Title of Journal : MATERIALS CHARACTERIZATION
  • Page Numbers: pp.233-239

Abstract

In this work, the boronizing of Fe-Mn binary alloys at 0.42, 0.76 and 0.94 wt.% Mn was carried out in a solid medium using the powder pack method. In this method, commercial Ekabor-II boron source and activator (ferro-silicon) were thoroughly mixed to form the boriding medium. The samples were boronized in an electrical resistance furnace for exposure times of 2, 4, 6 and 8 h at 1173 K under atmospheric pressure and a series of boronized samples in the temperature range 1073-1373 K for 3 h. After the furnace process, boronized samples were removed from the furnace and cooled in air. Afterwards, the boride layers generated by the pack-boronizing process were characterized by optical microscopy, scanning electron microscopy, XRD analysis, Vickers microhardness and tensile testing. The generated boride layers, showing a saw-tooth morphology, had a surface microhardness in the range 1400-1270 HV0.1. It was shown that the values of yield stresses and ultimate tensile stresses were increased as the Mn content increases in the boronized Fe-Mn binary alloys. In contrast, the values of elongations determined from the stress-strain curves were decreased. Furthermore, it was found that the calculated mean value of the activation energy of boron diffusion was close to 119 J/mol. (C) 2009 Elsevier Inc. All rights reserved.