scholarly journals Pit to crack transition and corrosion fatigue lifetime reduction estimations by means of a short crack microstructural model

2021 ◽  
Vol 180 ◽  
pp. 109171
Author(s):  
J.A. Balbín ◽  
V. Chaves ◽  
N.O. Larrosa
Keyword(s):  
Corrosion Fatigue ◽  
Short Crack ◽  
Fatigue Lifetime ◽  
Microstructural Model ◽  
Crack Transition

Prediction Approach for Corrosion Fatigue Life of Aircraft Structure Based on Probabilistic Fracture Mechanics

2006 ◽  
Vol 324-325 ◽  
pp. 943-946
Author(s):  
Xiao Ming Tan ◽  
Yue Liang Chen ◽  
Ping Jin
Keyword(s):  
Fatigue Life ◽  
Fracture Mechanics ◽  
Corrosion Fatigue ◽  
Failure Process ◽  
Short Crack ◽  
Aircraft Structure ◽  
Probabilistic Fracture Mechanics ◽  
Fracture Failure ◽  
Reliability Method ◽  
Prediction Approach

The corrosion, corrosion fatigue and fracture failure process of aircraft structure is directly concerned with combined effect of many factors, such as load, material characteristics, corrosive environment and so on. The process is very complicated, and there is typical randomness. Based on probabilistic fracture mechanics, with consideration of the limitation of the conventional probabilistic approaches for prediction of corrosion fatigue life of aircraft structure at present, and a new reliability approach under loading spectrum was proposed, in which corrosion damage and fatigue crack damage was united as a same damage parameter. Short crack and long crack growth behavior was separately discussed, and influence of short crack aspect ratio on structure life was discussed. The Advanced First-Order Reliability Method, Importance Sampling Method and iteratively advanced Second-Order Reliability Method were used to compute the fracture failure probability. The results show that the model is feasible. By sensitivity analysis of random parameter, the important parameter was obtained, which helped to monitor the structure fatigue life.

x-The Effect of Microstructure on the Corrosion Fatigue Property of A7N01P-T4 Aluminum Alloy Welding Joints

CORROSION ◽  
10.5006/2805 ◽  
2018 ◽  
Vol 74 (11) ◽  
pp. 1229-1236
Author(s):  
Feng Xiao ◽  
Jiangli An ◽  
Hui Chen ◽  
P. Li ◽  
Wei Gao
Keyword(s):  
Grain Boundaries ◽  
Corrosion Fatigue ◽  
Fatigue Property ◽  
Short Crack ◽  
Al Alloy ◽  
Second Phase ◽  
Test Results ◽  
Second Phase Particles ◽  
The Matrix ◽  
Almost All

The corrosion fatigue short crack propagation (CFSCP) behavior of A7N01P-T4 Al alloy welded joints in 3.5 wt% NaCl solution has been investigated. The test results indicate that the CFSCP followed a cyclical type of growth. Microscopic study shows that almost all second-phase particles are distributed along the grain boundary areas. These particles were easily dissolved during the corrosion fatigue test, resulting in weak grain boundaries. Therefore, the fatigue short crack will grow along the winding grain boundaries. While the second-phase particles on the grain boundaries were the main factor to cause the intergranular crack. Transgranular cracking may occur to the coarse grains in the matrix, which indicate that grain size also has a strong influence on the CFSCP behavior of A7N01P-T4 Al alloy.

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

2015 ◽  
Vol 227 ◽  
pp. 3-6
Author(s):  
Mikolaj Lukaszewicz ◽  
Shen Gi Zhou ◽  
Alan Turnbull
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
Potential Drop ◽  
Crack Size ◽  
Short Crack ◽  
Additional Contribution ◽  
Small Cracks ◽  
Turbine Steel

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 SO42- 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.

Examination and prediction of corrosion fatigue damage and inhibition

2017 ◽  
Vol 35 (4-5) ◽  
pp. 355-363
Author(s):  
Sarah E. Galyon Dorman ◽  
Justin W. Rausch ◽  
Saravanan Arunachalam ◽  
Scott A. Fawaz
Keyword(s):  
Fatigue Damage ◽  
Corrosion Fatigue ◽  
Mechanical Damage ◽  
Corrosion Damage ◽  
The United States ◽  
United States Department ◽  
Management Philosophy ◽  
Weapon Systems ◽  
Calcium Molybdate ◽  
Crack Transition

AbstractThe United States Department of Defense (DoD) estimated that the annual cost of corrosion to weapon systems and infrastructure in 2014 exceeded $18 billion and that the number was likely to continue to rise. Corrosion affects military readiness by taking critical weapon systems out of action, due to the degradation of equipment. Unfortunately, as the warfighters demand more from their systems, corrosion prevention and control is frequently traded during the acquisition cycle for weapon system performance. As a result, the DoD remains entrenched in a find-and-fix corrosion management philosophy which is expensive and unsustainable. Better standardized laboratory procedures are needed to help the DoD develop (1) a fundamental understanding of corrosion damage, (2) material performance data relevant to corrosion damage, (3) prediction methodologies to help mitigate the effects of corrosion nucleated damage and (4) to develop an understanding of how corrosion preventative coatings can slow mechanical damage. This paper addresses the effect of the corrosion inhibitors strontium chromate and calcium molybdate in concentrations relevant to service on corrosion fatigue damage as well as presents development of a test methodology for the examination of the corrosion pit-to-fatigue crack transition to help the DoD improve corrosion protection system selection.

scholarly journals Influence of Pitting Corrosion on Fatigue and Corrosion Fatigue of Ship and Offshore Structures, Part II: Load - Pit - Crack Interaction

2015 ◽  
Vol 22 (3) ◽  
pp. 57-66 ◽  
Author(s):  
Marek Jakubowski
Keyword(s):  
Fatigue Crack ◽  
Corrosion Fatigue ◽  
Stress Concentrator ◽  
Offshore Structures ◽  
General Corrosion ◽  
Crack Interaction ◽  
Anticorrosion Protection ◽  
Pit Nucleation ◽  
Corrosion Pits ◽  
Crack Transition

Abstract In the paper has been discussed influence of stresses on general corrosion rate and corrosion pit nucleation rate and growth , whose presence has been questioned by some authors but accepted by most of them. Influence of roughness of pit walls on fatigue life of a plate suffering pit corrosion and presence of the so called „ non-damaging” pits which never lead to initiation of fatigue crack, has been presented. Possibility of prediction of pit-to-crack transition moment by two different ways, i.e. considering a pit a stress concentrator or an equivalent crack, has been analyzed. Also, influence of statistical distribution of depth of corrosion pits as well as anticorrosion protection on fatigue and corrosion fatigue has been described.

scholarly journals Corrosion-fatigue lifetime of Aluminium–Copper–Lithium alloy 2050 in chloride solution

2015 ◽  
Vol 87 ◽  
pp. 681-692 ◽  
Author(s):  
M. Guérin ◽  
J. Alexis ◽  
E. Andrieu ◽  
C. Blanc ◽  
G. Odemer
Keyword(s):  
Corrosion Fatigue ◽  
Chloride Solution ◽  
Fatigue Lifetime ◽  
Lithium Alloy ◽  
Aluminium Copper
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