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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.

In order to study the mechanism of decreasing tensile strength and elongation of Austempered Ductile Cast Iron (ADI) in the wet condition, various tension tests and impact tests were carried out. Three point bending fatigue tests were carried out on ADI and annealed 0.55% carbon steel to clarify the influence of water on fatigue strength. The main conclusions are as follow. Embrittlement by water begins when plastic deformation starts in a tension test. The fatigue limit of ADI in water showed a lower value than that in air. The influence of a water environment on fatigue behaviour was similar to that of annealed 0.55% carbon steel. Embrittlement such as that in a tension test was not observed in a fatigue test.

In this paper, the corrosion-fatigue behavior of 301L stainless steel (SS) welded joints using narrow gap laser wire welding under the different stress ratio and concentrations of Cl${}^{-}$ has been investigated. Corrosion fatigue life curve (S-N) under different conditions was tested and fitted to obtain the fatigue limit. The microstructures and fracture surfaces of specimens were examined by optical microscopy (OM) and scanning electron microscopy (SEM). EBSD results have shown that chromium depletion in the weld heat-affected zone (HAZ) contributes to the decrease of corrosion fatigue properties in the HAZ.

The corrosion fatigue cracks propagation behavior of A7N01P-T4 and A7N01S-T5 aluminum alloys in 3.5 wt.% NaCl solution and air were studied by single side notch corrosion fatigue tests (SNET). The crack growth rate (da/dN) was measured and the crack propagation mechanism was analyzed by scanning electron microscopic analysis. The results showed that the corrosion fatigue cracks growth rate of A7N01S-T5 alloy in air and 3.5 wt.% NaCl solution is faster than that of A7N01P-T4 alloy. The crack propagation follows a mixed intergranular and transgranular mode. The anodic dissolution and hydrogen embrittlement accelerate the propagation of corrosion fatigue crack of 7-series Al alloy in 3.5 wt.% NaCl solution. The corrosion resistance and fatigue crack propagation are related to the strength of the alloys and the density of grain boundaries.

The fatigue crack initiation life and growth rate are affected by experimental conditions. A corrosive environment can be created in a laboratory by means of dropping salt water onto the specimen surface, spraying chloride mist into the experimental chamber, etc. In the case of smooth specimens of some metals, fatigue life is shortened and the fatigue limit disappears under such corrosive experimental conditions. In this study, the effects of intermittent spraying of 3% NaCl solution-mist on corrosion fatigue behavior were investigated. The material used was 0.37% carbon steel. This is called JIS S35C in Japan. Spraying of 3% NaCl solution-mist attacked the surface layer of the specimen. It is well known that the pitting, oxidation–reduction reaction, etc. affect the fatigue strength of metals in a corrosive environment. We carried out corrosion fatigue tests with smooth specimens, holed specimens and slit specimens. Then the effects of such specimen geometry on the fatigue strength were investigated when the NaCl solution-mist was sprayed onto the specimen surface. In the case of lower stress amplitude application in slit specimens, the fatigue life in a corrosive atmosphere was longer than that in the open air. It is discussed that the behavior is related to the crack closure which happens when the oxide builds up and clogs the crack or slit.