Effects of Hydrogen on Fatigue Crack Growth of Iron Aluminides

1994 ◽  
Vol 364 ◽  
Author(s):  
A. Castagna ◽  
N.S Stoloff
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Al Alloys ◽  
Moist Air ◽  
Stress Intensity Range ◽  
Low Levels ◽  
Structural Iron ◽  
Fatigue Crack Growth Testing ◽  
Crack Growth Rates

AbstractThree Fe-Al alloys, FAP-Y, FA-129, and Fe-35a%Al, containing 16, 28, and 35a%Al, respectively, have been subjected to fatigue crack growth testing in moist air, in oxygen, and in gaseous hydrogen. In each case hydrogen and air were embrittling. Crack growth rates increased significantly as frequency decreased. Fatigue crack growth results have been compared with those for other structural iron-base alloys. Surprisingly, FAP-Y displays the highest crack growth rate of any alloy examined, except at very low levels of stress intensity range. The mechanisms for embrittlement by hydrogen and by moisture in air are discussed.

Prediction of Fatigue Crack Growth of Aged Hardening Al-Alloys under Variable Amplitude Loading

2014 ◽  
Vol 891-892 ◽  
pp. 1729-1735
Author(s):  
Mustapha Benachour ◽  
Boumedienne Zeggai ◽  
Nadjia Benachour ◽  
Mohamed Benguediab ◽  
Abdelkader Belmokhtar
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Al Alloys ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
R Ratio ◽  
Single Overload ◽  
Crack Growth Rates

In this investigation, variable amplitude loading effect was studied on aged hardening Al-alloys in series 2000 and 7000. Generalised Willenborg model was used in order to show loading interaction effects (overload effects). Variable amplitude loading under different form of spectrum has affected highly the fatigue life and fatigue crack growth rates. Fatigue lives were increased and fatigue crack growth rates (FCGRs) were decreased in increasing of overload ratio in single overload case. In application of overload band, the fatigue lives and FCGRs were affected by band overload and R-ratio of them when level in FCGRs was increased.

Super-Long Life Fatigue Behavior of Structural Aluminum Alloys

2004 ◽  
Vol 261-263 ◽  
pp. 1287-1294 ◽  
Author(s):  
Qing Yuan Wang ◽  
Norio Kawagoishi ◽  
Nu Yan ◽  
Q. Chen
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Al Alloys ◽  
Stress Intensity Factor Range ◽  
Initiation And Propagation ◽  
Small Cracks ◽  
Long Life ◽  
Crack Growth Rates

The objective of this study is to determine very long life fatigue and near threshold fatigue crack growth behaviors of 7075/T6 and 6061/T6 Al-alloys using piezoelectric accelerated fatigue at 19.5KHz. The experimental results show the fatigue failure can occur beyond 107, even 109 cycles, and endurance limits could not be obtained in the Al-alloys until 109 cycles. Fatigue voids are noticed on fatigue fracture in both alloys. By using scanning electron microscopy (SEM), the crack initiation and propagation behaviors have been examined. Fatigue crack growth rates of small cracks in the Al-alloys are found to be greater than those of large cracks at the same stress intensity factor range.

scholarly journals Advantageous Description of Short Fatigue Crack Growth Rates in Austenitic Stainless Steels with Distinct Properties

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 475
Author(s):  
Lukáš Trávníček ◽  
Ivo Kuběna ◽  
Veronika Mazánová ◽  
Tomáš Vojtek ◽  
Jaroslav Polák ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Large Scale ◽  
J Integral ◽  
Scale Yielding ◽  
Residual Fatigue ◽  
Crack Growth Rates

In this work two approaches to the description of short fatigue crack growth rate under large-scale yielding condition were comprehensively tested: (i) plastic component of the J-integral and (ii) Polák model of crack propagation. The ability to predict residual fatigue life of bodies with short initial cracks was studied for stainless steels Sanicro 25 and 304L. Despite their coarse microstructure and very different cyclic stress–strain response, the employed continuum mechanics models were found to give satisfactory results. Finite element modeling was used to determine the J-integrals and to simulate the evolution of crack front shapes, which corresponded to the real cracks observed on the fracture surfaces of the specimens. Residual fatigue lives estimated by these models were in good agreement with the number of cycles to failure of individual test specimens strained at various total strain amplitudes. Moreover, the crack growth rates of both investigated materials fell onto the same curve that was previously obtained for other steels with different properties. Such a “master curve” was achieved using the plastic part of J-integral and it has the potential of being an advantageous tool to model the fatigue crack propagation under large-scale yielding regime without a need of any additional experimental data.

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