Tension-compressionandrotating-bendingfatiguetestswerecarriedoutusingaluminiumalloy 2024-T3, in 3% NaCl solution. The corrosion pit growth characteristics, and alsothe fatigue crack initiation and propagation behaviour were investigated in detail. Theresults obtained are summarized as follows: (i) Most of corrosion fatigue life (60–80%)is occupied with a period of corrosion pit growth at low-stress amplitude. The corrosionpit growth law can be expressed as functions of stress amplitude σ a and an elapsed time t . (ii) The critical stress intensity factor for crack initiation from the corrosion pit wasdetermined as 0.25 MPa√m. This value is the same as the threshold stress intensity factorrange for crack propagation. (iii) Corrosion fatigue life can be estimated on the basis ofcorrosion pit growth law and crack propagation law. The estimated fatigue lives agree wellwith the experimental data. Keywords corrosion fatigue; corrosion pit; stress amplitude; stress frequency.INTRODUCTIONAluminium alloys have been widely used as structuralmembersoftransportmachines,suchasshipsandaircraftsfor the purpose of reducing their weight. Such structuresare usually exposed to the natural environment during theoperation.It is well known that metal fatigue life is lowered sub-stantially by the action of a corrosive environment whencompared with that in an inert atmosphere. This is be-cause a corrosion pit can generate and grow on the mate-rial surface, followed by crack initiation and propagationin corrosive environments, even at very low-stress ranges.Therefore, for quantitative analysis of the corrosion fa-tigue life, it is very important to clarify the corrosion pitgrowth characteristics and the crack initiation behaviourfrom the corrosion pit. Until now, many researches oncorrosion pit growth characteristics, and crack initiationand propagation behaviour have been made.Wan

Prediction of corrosion fatigue lives of aluminium alloy on the basis of corrosion pit growth law

The synergistic combination of mechanical fatigue stresses and environmental agents acting together can be more detrimental than that of the summation of the contributions of each mechanism acting separately. Major attempts to understand the contribution of the different agents (microstructure, chemical composition of environment, temperature, loading conditions, etc.) have been reported in the literature. Nevertheless, current knowledge is insufficient to address life estimation with a sound physical basis from the initiation of localised corrosion (such as pitting) to the estimation of crack propagation. Major simplifications and assumptions have been required in the development of life prediction methodologies. This paper reviews recent efforts made by the different interested parties, in both academia and industry, in the development of corrosion fatigue (CF) lifetime prediction procedures. The paper mainly focuses on the methodologies proposed in the literature for oil and gas, nuclear, energ...

/pdf/corrosion-fatigue-a-review-of-damage-tolerance-models-13rs9fjhve.pdf

Corrosion-fatigue: a review of damage tolerance models

The influence of pre-straining on the high-cycle fatigue performance of two hot-dip galvanised car body steels

Influence of the microstructure on the thermal shock behavior of cemented carbides

An improved method for the determination of the maximum thermal stress induced during a quench test

Study on the thermal shock behavior of cermets and cemented carbides

Distribution of Corrosion Fatigue Crack Lengths in Carbon Steel : 1st Report, The Cracks Which Grow Individually

The thermal shock behavior of cermets and cemented carbides was studied in detail by using unnotched smooth bar specimens. Thermal shock was given to the specimens by plunging them into a water bath at 20°C. After the thermal shock experiments, bending strength, micro vickers hardness and fracture toughness of the specimens were investigated. As a result, two different types of thermal shock behavior were observed between cermets and cemented carbides. These differences indicate that microcracks occur more easily in cemented carbides than cermets during thermal shock experiments.

Study on thermal shock behavior of cermets and cemented carbides.

This note gives a theoretical solution to a disk with an eccentric circular hole when it is compressed by two equal and opposite forces acting at a radius of the outer circle on the centre of inner circle. The method of solution adds to the given stress system a suitable biharmonic function, which gives no normal and tangential stress on the outer edge. The parametric coefficients involved in the solution are adjusted so as to satisfy the boundary conditions at the inner edge. Bipolar coordinates are used in the solution, by means of which explicit expressions are obtained for the parametric coefficients. Formulas of stress along the edge of circles are derived, and, in particular, the stress distributions of the inner hole are calculated.

Kazyu Miyao

Papers

Study on the thermal shock behavior of cermets and cemented carbides

Distribution of Corrosion Fatigue Crack Lengths in Carbon Steel : 1st Report, The Cracks Which Grow Individually

Study on thermal shock behavior of cermets and cemented carbides.

Stresses in a Circular Disk with an Eccentric Circular Hole under Radial Forces

Stresses in a Plate Containing a Circular Hole with a Notch