Definition - What does Corrosion Fatigue mean?
This refers to a fatigue that is found in a material that has experienced corrosion. It can also be referred to as a type of gradation material. The material experiences a mechanical degradation which occurs in the combination of cyclic loading and joint action corrosion.
In 1930, the effects of corrosion conditions on the fatigue properties of a metal were studied. It is not the same phenomena as stress corrosion cracking. Corrosive conditions lead to failure, growth of degradation, and development of brittle cracks. Corrosion fatigue is considered a type of tensile stress.
Corrosionpedia explains Corrosion Fatigue
A great number of engineering structures are subjected to alternating conditions of stress. At some point, the structures are exposed to conditions that are very harmful to their lifespan. In turn, the strength of these structures is greatly affected. Some of the materials that are commonly used in engineering structures that undergo thorough fatigue include titanium alloys, aluminum alloys and steel, among others. The wider application of these materials depends on their resistance to corrosive fatigue.
Materials that have high strength are developed through the use of the alloying or the heat treatment process so that they can meet the requirements of technological applications in engineering structures. Higher fatigue limits will be exhibited by materials that have undergone the heat treatment process because they have higher strength. Such materials find their applications in places where there is high fatigue loading.
Unfortunately, the presence of conditions that are corrosive in cases where there is fatigue loading will automatically decrease the advantage of high strength. This is because the fatigue will increase as strength for particular types of alloys decreases. In an aqueous solution, the corrosion fatigue behaves like an electrochemical component. Slip bands or pitting are the major causes of fractures. Cathodic protection, inhibition as well as the addition of alloys can be good ways of reducing fatigue corrosion. The material resistance to cracks that result from fatigue corrosion can also be prevented by surface treatment processes such as shot peening, nitriding, plating and cladding.