STUDY ON THE PIT GROWTH DURING CORROSION FATIGUE OF ALUMINUM ALLOY

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3975-3980 ◽  
Author(s):  
S. ISHIHARA ◽  
S. SAKA ◽  
Z. Y. NAN ◽  
T. GOSHIMA ◽  
H. SHIBATA ◽  
...  

Tension-compression and rotating bending fatigue tests were carried out using aluminum alloy 2024-T3 in 3% sodium chloride solution. During corrosion fatigue process, many corrosion pits were initiated at the early stage, and cracks were initiated from the pits. The characteristics of the pit growth were investigated in detail. The critical condition for crack initiation from the corrosion pit was also studied. Crack initiation periods during corrosion fatigue were evaluated on the basis of the corrosion pit growth law.

2010 ◽  
Vol 1276 ◽  
Author(s):  
Víctor H. M. Lemus ◽  
Gonzalo M. D. Almaraz ◽  
J. Jesús V. Lopez

AbstractThis work deals with rotating bending fatigue tests on aluminum alloy 6061-T6, under loading condition close to the elastic limit of the material. Results have been obtained for three types of specimens: without artificial pitting, specimens with one artificial pitting hole and specimens with two neighboring artificial pitting holes. Results show that fatigue endurance is reduced in the case of one pitting hole and considerably for two neighboring pitting holes. In order to explain this behavior, numerical analysis by FE are carried out to determine the stress concentrations for the three types of specimens. It is found that the stress concentration for two neighboring pitting holes is an exponential function of the separation between the two holes, under uniaxial loading. The probability to find two or more neighboring pitting holes in real industrial materials, such as cast iron, corroded or pitting metallic alloys is high; then, the stress concentration for two or more neighboring pitting holes needs to be considered for the fatigue prediction life under fatigue loading and corrosion attack applications.


2012 ◽  
Vol 1373 ◽  
Author(s):  
G. M. Domínguez Almaraz ◽  
J. L. Ávila Ambriz ◽  
E. Cadenas Calderón ◽  
J. J. Villalón López

ABSTRACTRotating bending fatigue test are carried out on the aluminum alloy 6063-T5 for corroded and non corroded specimens. Special attention is devoted to fatigue endurance reduction caused by controlled surface corrosion on corroded specimens. Corrosion attack is implemented by submersion of specimens in an acid solution for: two, four and six minutes in order to induce three degrees of surface corrosion. The corrosion agent is a solution of hydrochloric acid with a PH close to 0.8 and solution concentration of 38%. Rotating bending fatigue tests at frequency of 50 Hz, room temperature and without environmental humidity control are carried out on 4 types of specimens: without corrosion and 2, 4, and 6 minutes immersed in the solution of hydrochloric acid. Results are analyzed regarding the corrosion effect on fatigue endurance and conclusion are enlisted concerning rotating bending fatigue tests and corrosion attack on this aluminum alloy.


2008 ◽  
Vol 385-387 ◽  
pp. 197-200 ◽  
Author(s):  
T. Kanemaru ◽  
Norio Kawagoishi ◽  
Eiji Kondo ◽  
Qing Yuan Wang ◽  
Y. Ohzono

In order to investigate the influence of grain size on notch sensitivities in fatigue of a fine-grained carbon steel, rotating bending fatigue tests were carried out using specimens with a V-grooved circumferential notch of commercial fine-grained carbon steel with grain size of 6.5µm. The results were compared with those of a larger grain sized carbon steel (grain size: 20 µm) and the notch sensitivities were evaluated based on Linear notch mechanics proposed by Nisitani. Notch sensitivities for both of fatigue limits for a crack initiation and its propagation of the fine grained steel were high. The results were discussed from the view points of the size of area related to crack initiation and the crack growth resistance.


2013 ◽  
Vol 577-578 ◽  
pp. 421-424 ◽  
Author(s):  
Ryuichiro Ebara ◽  
Yuya Miyoshi

Ultrasonic Corrosion Fatigue Tests were Conducted for SUS329J3L in Air and 3%NaCl Aqueous Solution. Reduction of Giga-Cycle Corrosion Fatigue Strength was 12.5%. Corrosion Pit was Observed on Corrosion Fatigue Crack Initiation Area. Striation was Predominantly Observed on Crack Propagation Area both in Air and 3% Nacl Aqueous Solution. it can be Concluded that the Reduction of Corrosion Fatigue Strength of SUS329J3L is due to the Corrosion Pit Formation at Corrosion Fatigue Crack Initiation Area.


2009 ◽  
Vol 65 ◽  
pp. 79-88
Author(s):  
Gonzalo Domínguez Almaraz ◽  
Edgar Tapia Silva ◽  
Mauricio Guzmán Tapia ◽  
Jesús Villalón López

This work deals with rotating bending fatigue tests at high speed (150 Hz), carried out on aluminum alloy AISI-SAE 6061-T6 for which the highest experimental stress inside the specimen is close to the elastic limit of material. Simulation results are obtained by Visual Nastran software in order to determine the numerical stress and strain distributions inside the specimen; then, this information is used for the experimental set up. A general description of experimental test machine and experimental conditions are developed in first sections, following section present the experimental results and discussion about the observed failure origin related to discontinuities and the associated high stress zones. A principal contribution of this work is related to the analysis of fracture surfaces and its correlation with experimental fatigue endurance: a simple model is proposed for the prediction of fatigue life of this aluminum alloy under high speed rotating bending fatigue tests, based on the surface density of associated fatigue macro-plastic deformation zones close the crack initiation.


2012 ◽  
Vol 1485 ◽  
pp. 53-58 ◽  
Author(s):  
G. M. Domínguez-Almaraz ◽  
J. L. Ávila-Ambriz ◽  
F. Peyraut ◽  
E. Cadenas-Calderón

ABSTRACTCorrosion attack is implemented on the aluminum alloy AISI 6063-T5 for six different non corroded and pre-corroded specimens. Concerning pre-corroded specimens, they are divided in two groups; the first one is immersed for 1 and 2 minutes in hydrochloric acid with 20% concentration, and the second group for 2, 4, 6 minutes of immersion but in HCl with 38% of concentration. Rotating bending fatigue tests are carried out on corroded and non-corroded specimens at the frequency of 50 Hz, at room temperature and without control of environmental humidity. Loading conditions are fixed by Finite Element numerical simulation; the loading ranges are 90%, 80%, 70% and 60% of the yield stress of this aluminum alloy. A numerical simulation study is carried out by means of the Ansys software to investigate the stress concentration factor variation induced by the proximity of two close pitting holes: in longitudinal and transversal direction regarding the principal applying loading. Finally, optical microscopy is used to analyze the fracture surfaces in longitudinal and transversal directions, in order to establish possible causes of fatigue fracture.


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