Novel Concepts on the Growth of Corrosion Fatigue Small and Short Cracks

Mikolaj Lukaszewicz; Shen Gi Zhou; Alan Turnbull

doi:10.4028/www.scientific.net/SSP.227.3

Paper Titles

Preface and Organizing Committee

Novel Concepts on the Growth of Corrosion Fatigue Small and Short Cracks
p.3

Corrosion Fatigue Crack Propagation Rates for Steam Turbine Blade 13% Cr Steels
p.7

Corrosion Behaviour of Amorphous and Nanocrystalline Alloys
p.11

Influence of Plastic Deformation on the Corrosion Behaviour of As-Cast AlMg2 and AlCu4Mg1 Aluminium Alloys in NaCl Solution
p.15

Influence of the Crystallographic Orientation of Grains and Plastic Deformation on the Electrochemical Behavior of Pure Aluminum in Sodium Chloride Solution
p.19

Structure and Corrosion Behavior of Mg-Cu-Y-(Zn,Ni) Bulk Metallic Glasses
p.23

The Influence of Deformation the Corrosion Resistance of Titanium Grade2
p.27

Influence of Ageing on the Corrosion Resistance of the ZnAl22Cu3 and ZnAl40Cu3 Alloys
p.31

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Novel Concepts on the Growth of Corrosion Fatigue Small and Short Cracks

Abstract:

Corrosion fatigue small, short and long crack growth rates have been determined for a 12Cr steam turbine steel in aerated 300 ppb Cl^- + 300 ppb SO₄^2- solution and in air at 90 °C. The crack growth rate for short and long cracks was monitored by direct current potential drop (DCPD) and for the small cracks by combining high resolution optical microscopy and DCPD. Comparison of the fatigue growth rate demonstrated that in solution the short crack growth rate was remarkably enhanced in comparison to long cracks, when the crack size is smaller than 250 μm. This enhancement was attributed to the electrochemical crack size effect associated with greater anodic polarisation of the short crack in such low conductivity solution. However, such enhanced growth was not observed for small cracks, which was rationalised on the basis of additional contribution of current from the pit limiting crack-tip polarisation.

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Periodical:

Solid State Phenomena (Volume 227)

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3-6

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https://doi.org/10.4028/www.scientific.net/SSP.227.3

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Online since:

January 2015

Authors:

Mikolaj Lukaszewicz*, Shen Gi Zhou, Alan Turnbull

Keywords:

Blade Steel, Corrosion Fatigue, Small Crack, Steam Turbine

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