J. Mater. Sci. Technol. ›› 1989, Vol. 5 ›› Issue (2): 101-112.

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Unusual W-shaped Galvanic Cell Model of ISCC of α-brass in Neutral Mattsson's Solution

WU Shaobin;R. J. Arsenault;I. R. Kramer Metallurgical Materials Laboratory, University of Maryland, USA.   

  1. MetallurgicalMaterialsLaboratory,UniversityofMaryland,USA.;MetallurgicalMaterialsLaboratory,UniversityofMaryland,USA.;MetallurgicalMaterialsLaboratory,UniversityofMaryland,USA.
  • 收稿日期:1989-03-28 修回日期:1989-03-28 出版日期:1989-03-28 发布日期:2009-10-10

Unusual W-shaped Galvanic Cell Model of ISCC of α-brass in Neutral Mattsson's Solution

WU Shaobin;R. J. Arsenault;I. R. Kramer Metallurgical Materials Laboratory, University of Maryland, USA.   

  • Received:1989-03-28 Revised:1989-03-28 Online:1989-03-28 Published:2009-10-10

摘要: <正> Intergranular stress corrosion cracking(ISCC) of α-brass in neutral Mattsson's solutionwas found to be controlled by an unusual"W"-shaped galvanic cell whose cathode is thegrain boundary oxide film (G.B.0. film) andsurface film and the anode is fresh metal atthe cracked tip on both sides of the G.B.0.film. Redox reactions involved in the cellhave been proposed here. According to thismdel, initidtion of ISCC is caused by therupturing of surface film along grain boundaries,thus forming a galvanic cell. Propagation ofISCC resulted from alternate advances of G.B.0.film and dissolution on both sides of G.B.0.film caused by the effect of electrochemicalreaction. This work developed an effective approachto investigate the embrittlement process atthe tip of the crack, by increasing the lengthof the embrittlement region through constantstrain test and distinguishing the morphologyand the nature of the corrosion products byoptical microscopy and scanning electronmicroscopy (SEH).

Abstract: Intergranular stress corrosion cracking (ISCC) of α-brass in neutral Mattsson's solution was found to be controlled by an unusual "W"-shaped galvanic cell whose cathode is the grain boundary oxide film (G.B.0. film) and surface film and the anode is fresh metal at the cracked tip on both sides of the G.B.0. film. Redox reactions involved in the cell have been proposed here. According to this mdel, initidtion of ISCC is caused by the rupturing of surface film along grain boundaries, thus forming a galvanic cell. Propagation of ISCC resulted from alternate advances of G.B.0. film and dissolution on both sides of G.B.0. film caused by the effect of electrochemical reaction. This work developed an effective approach to investigate the embrittlement process at the tip of the crack, by increasing the length of the embrittlement region through constant strain test and distinguishing the morphology and the nature of the corrosion products by optical microscopy and scanning electron microscopy (SEH).

Key words: α-brass, intergranular stress corrosion cracking, W-shaped cell model, grain boundary oxide film