CRACK INITIATION I N CORROSION FATIGUE AT DEFINED GRAIN BOUNDARIES I N BI- AND POLYCRYSTALS

1990 ◽  
Vol 51 (C1) ◽  
pp. C1-703-C1-708
Author(s):  
J. WALTERSDORF ◽  
H. VEHOFF
Keyword(s):  
Crack Initiation ◽  
Grain Boundaries ◽  
Corrosion Fatigue

Prediction of corrosion fatigue crack initiation behavior of A7N01P-T4 aluminum alloy welded joints

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744034 ◽  
Author(s):  
J. An ◽  
J. Chen ◽  
G. Gou ◽  
H. Chen ◽  
W. Wang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Crack Initiation ◽  
Grain Boundaries ◽  
Corrosion Fatigue ◽  
Welded Joints ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Corrosion Fatigue Crack ◽  
Second Phases

Through investigating the corrosion fatigue crack initiation behavior of A7N01P-T4 aluminum alloy welded joints in 3.5 wt.% NaCl solution, corrosion fatigue crack initiation life is formulated as [Formula: see text] and the mechanism of corrosion fatigue crack initiation is proposed. SEM and TEM tests revealed that several corrosion fatigue cracks formed asynchronously and the first crack does not necessarily develop into the leading crack. The uneven reticular dislocations produced by fatigue loading are prone to piling up and tangling near the grain boundaries or the second phases and form the “high dislocation-density region” (HDDR), which acts as an anode in microbatteries and dissolved to form small crack. Thus the etching pits, HDDR near the grain boundaries and second phases are confirmed as the main causes inducing the initiation of fatigue crack.

Technique d'observation de surface in situ (TOSIS) :

1996 ◽  
Vol 84 ◽  
pp. 17-22
Author(s):  
A. Ranaivoarisoa ◽  
J. M. Olive ◽  
D. Desjardins
Keyword(s):  
Aqueous Solution ◽  
Crack Initiation ◽  
Grain Boundaries ◽  
Growth Rates ◽  
Triple Junction ◽  
Crack Nucleation ◽  
Initiation Time ◽  
Mesoscopic Scale ◽  
Crack Growth Rates

An optical method named In Situ Surface Observation Technique (ISSOT) is presented in this paper. This method is used to detect crack nucleation from a flaw (here a pit) at mesoscopic scale during a triangular push-pull cycling test under the control of charge amplitude in aqueous solution ofMgCl2 at 117°C. It can be found that the crack initiation time determined by using this technique represents 2 % of that estimated from a mechanical criterion. Moreover, the follow of the crack tip evolution by the ISSOT allows to measure average local crack growth rates. It has been shown that the variations of the latter were related to the effects of barriers such as grain boundaries, twin boundaries and grain boundaries triple junction.

Corrosion fatigue crack initiation in ultrafine-grained near-α titanium alloy PT7M prepared by Rotary Swaging

2019 ◽  
Vol 790 ◽  
pp. 347-362 ◽  
Author(s):  
V.N. Chuvil'deev ◽  
V.I. Kopylov ◽  
N.N. Berendeev ◽  
A.A. Murashov ◽  
A.V. Nokhrin ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Fatigue Crack ◽  
Crack Initiation ◽  
Corrosion Fatigue ◽  
Fatigue Crack Initiation ◽  
Corrosion Fatigue Crack ◽  
Rotary Swaging ◽  
Ultrafine Grained

3D time-resolved observations of corrosion and corrosion-fatigue crack initiation and growth in peak-aged Al 7075 using synchrotron X-ray tomography

2018 ◽  
Vol 138 ◽  
pp. 340-352 ◽  
Author(s):  
Tyler J. Stannard ◽  
Jason J. Williams ◽  
Sudhanshu S. Singh ◽  
Arun Sundar Sundaram Singaravelu ◽  
Xianghui Xiao ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Corrosion Fatigue ◽  
Fatigue Crack Initiation ◽  
Time Resolved ◽  
X Ray ◽  
Corrosion Fatigue Crack ◽  
Al 7075 ◽  
Peak Aged
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