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Oxidation and Corrosion
Published in Alan Cottrell, An Introduction to Metallurgy, 2019
We do not yet have an established, detailed, theory of corrosion fatigue. The form of the fatigue crack is usually not much altered by the presence of the corrosive agent. The crack merely grows faster. Possibly, a process similar to that of Fig. 23.7 operates. During the tensile phase of the fatigue cycle the tip of the crack is stretched plastically and this exposes plastically strained metal there to the corrosive agent which is simultaneously sucked into the fatigue crack. Most of the methods developed for protection from simple corrosion, e.g. protective coatings, inhibitors, cathodic protection using sacrificial anodes, and those developed for protection from simple fatigue, e.g. shot-peening and surface alloying to promote compressive stresses in the surface, are also suitable for improving the corrosion-fatigue strengths of metals.
Fundamentals of Electrochemistry
Published in Héctor A. Videla, Manual of Biocorrosion, 2018
Corrosion fatigue is a special case of stress corrosion cracking where the simultaneous effects of cyclic stress and corrosion lead to failure. It occurs in a wider range of environments than stress corrosion cracking and it is almost always transgranular. In general, the sensitivity to cracking increases with increasing chloride concentration, tensile stress, and temperature. In all cases of stress corrosion cracking, just as with pitting corrosion, most of the total time to failure is an initiation time during which no cracks are visible. The cracking speed, once cracks have developed, is on the order of several millimeters per hour. Microorganisms can participate in these kinds of localized corrosion by the production of corrosion-enhancing metabolites such as acids and hydrogen sulfide. The effect of SRB and biogenic sulfur environments on the fatigue corrosion of steels in a marine environment is mentioned in recent literature.16–18
Biodegradation Mechanism and Influencing Factors of Mg and Its Alloys
Published in Yufeng Zheng, Magnesium Alloys as Degradable Biomaterials, 2015
Corrosion fatigue may be defined as the combined action of an aggressive environment and cyclic stress leading to premature failure of metals by cracking (Gastaldi et al. 2011). For orthopedic implants, the ultimate implant failure is usually associated with corrosion fatigue, which is the synergetic effect of electrochemical corrosion and cyclic mechanical loading (Azevedo 2003; Magnissalis et al. 2003). For vascular devices, the failure of a stent due to fatigue may result in loss of radial support of the stented vessel or in perforation of the vessel by the stent struts. It was estimated that approximately two thirds of the failures of vascular devices would result in patient death (James and Sire 2010).
Effect of ultrasonic impact treatment on corrosion fatigue performance of friction stir welded 2024-T4 aluminum alloy
Published in Corrosion Engineering, Science and Technology, 2022
Binghan Huang, Lei Wang, Xiaopeng Liu, Li Hui, Jiahui Cong, Song Zhou
Under the synergy and interaction of alternating stress and corrosive environment, the premature failure of materials or components below the yield strength of the material is called corrosion fatigue failure. Fatigue failure in welded joints is one of the major reasons for the failure of mechanical structures and typically starts from the surface or near the surface. Therefore, the overall mechanical properties of the joint can be improved by strengthening the surface of the welded joint by using various techniques, such as shot peening, hammering, rolling and plasma spraying, among others [2–4]. Surface strengthening endows the material with ideal surface performance without changing its overall performance and can be potentially used in various industries. Ultrasonic impact treatment (UIT) is a relatively new and promising method with the advantages of a lightweight actuator, flexible and convenient use, high efficiency, low noise, low cost and so on [5,6]. UIT produces residual compressive stress and microstructural changes on the surface of the workpiece by high-speed impact, improving the mechanical properties of the material. UIT exhibits good controllability, provides deep residual compressive stress layer and hardened layer and can be impacted for complex-shaped workpieces; thus, it bears considerable engineering value and theoretical significance [7].
Corrosion fatigue in DLC-coated articulating implants: an accelerated methodology to predict realistic interface lifetime
Published in Science and Technology of Advanced Materials, 2019
Ainhoa Pardo, Emilija Ilic, Kerstin Thorwarth, Michael Stiefel, Roland Hauert
The phenomenon that leads to the failure of an interface under simultaneous action of cyclic loads and chemical interaction is assigned in this article to corrosion fatigue. Typically, the corrosion fatigue of a bulk material is described by stress cycles to failure, S-N, or Wöhler curves. A highly localized plastic deformation during cyclic loading results in alteration of the material’s properties, leading to crack initiation and growth. The Wöhler curve represents the number of cycles needed to concentrate the plastic strain leading to crack initiation, growth, and subsequent material fatigue failure. A corrosive media can contribute to and accelerate the initiation time in a combined corrosion fatigue activity, and modify the endurance limit. In this study, similar corrosion fatigue failure concepts are adapted to the particular case of a buried interface. Instead of describing the critical stress, the proposed Wöhler-like curve considers the load at the interface. The justification is that the induced tangential force during the reciprocating sliding (Load·CoF) is proportional to the shear strength at the interface. Summarizing, this research proposes a fatigue-wear setup as the experimental methodology to introduce shear forces at the interface and therefore it will be used unconventionally to address the interface corrosion fatigue.
Contribution of research to the understanding and mitigation of environmentally assisted cracking in structural components of light water reactors
Published in Corrosion Engineering, Science and Technology, 2018
Cracking of girth welds in steam generator shells has affected a small number of US PWR plants [36]. This was considered to be due to a combination of factors including inadequate post-weld heat treatment (resulting in over-hard heat-affected zones), intermittent cyclic loading which introduces a corrosion fatigue component to cracking, inadequate feedwater deoxygenation and ingress of oxidising copper species. Mechanistically, these failures appear similar to SICC in German BWRs.