Download or read book Understanding the Mechanisms Controlling Stress Corrosion Cracking Through High resolution Characterization written by Zhao Shen and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Determination of Damage Initiation Mechanisms in Aerospace Alloys Due to Stress Corrosion Cracking Via In situ Microscale Characterization Techniques written by Remelisa P. Esteves and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aluminum alloys are used on aerospace vehicles due to their high strength-to-weight ratio, formability and machinability. However, they become vulnerable to stress corrosion cracking (SCC) during their service life.SCC is primarily caused by the material’s stress condition, a suitable corrosive environment and material susceptibility. It is also influenced by a mixture of electrochemical, mechanical, and chemical factors. Due to the complexity of SCC, tools with better resolution and sensitivity are needed to better understand the impact and interaction of the contributing factors. A vast amount of research has been done to study SCC behavior, but the scale of characterization must be reduced to elucidate the key initiation mechanisms. In this work, it is shown that SCC initiation was detected early via micro-digital image correlation (micro-DIC) prior to the crack being discernible in microscopy images. The initial effort to monitor stress corrosion cracking in AA7075-T6 involved using a pixel resolution of 3.825 microns/pixel, frame rate of 10-15 min/image and an airbrush nozzle diameter of 0.3 mm for the speckle pattern, which led to the detection of crack initiation at 98% failure load. By using a pixel resolution that is 6 times smaller, a frame rate of up to 60 times less time per image, and an airbrush nozzle that is 2 times smaller, the first observation of strain concentration marking the eventual failure region of the AA7075-T6 sample was detected as early as 58% failure load. When the micro-DIC technique was applied to study SCC behavior in additively manufactured AlSi10Mg, the first observation of localized strain marking the eventual failure region of the sample was detected at 78% failure load. X-ray synchrotron tomography was used to qualitatively assess the hydrogen bubble and precipitate formation and to quantitatively assess the post initiation crack growth in AA7075-T651. With improved micro-DIC parameters and correlation with experimental outcomes from x-ray synchrotron tomography, multiple factors contributing to SCC can be assessed to better understand the mechanisms of SCC initiation. Correlations of material exposure time and load with SCC initiation can provide data for developing corrosion control strategies and new and improved alloys or heat treatment, as well as understanding SCC behavior in alloys made through unconventional means, such as additive manufacturing. The impact of this work lies in the life extension of alloys and greater reusability and fatigue life extension of aerospace vehicles.

Download or read book High resolution Characterisation of Stress Corrosion Cracking written by Martina Meisnar and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understanding the Mechanisms of Stress Corrosion Cracking written by Karen Kruska and published by . This book was released on 2012 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors written by John H. Jackson and published by Springer. This book was released on 2018-12-20 with total page 2532 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two-volume set represents a collection of papers presented at the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems – Water Reactors. The purpose of this conference series is to foster an exchange of ideas about problems and their remedies in water-cooled nuclear power plants of today and the future. Contributions cover problems facing nickel-based alloys, stainless steels, pressure vessel and piping steels, zirconium alloys, and other alloys in water environments of relevance. Components covered include pressure boundary components, reactor vessels and internals, steam generators, fuel cladding, irradiated components, fuel storage containers, and balance of plant components and systems.

Download or read book Experiments to Explore the Mechanisms of Stress Corrosion Cracking written by Jie Gao and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Stress corrosion cracking (SCC) is a type of subcritical cracking of materials that occurs when a SCC susceptible material is simultaneously stressed in tension (applied or residual) and exposed to a specific corrosive environment. Failure of materials due to SCC could occur at stress levels much lower than the allowable service stress, causing catastrophic consequences. Decades of efforts to investigate the SCC phenomena have established the general behaviors of different materials during SCC and it is widely accepted that a susceptible material, tensile stress, and a specific corrosive environment are the prerequisites for the occurrence of SCC. However, the fundamental mechanisms behind the apparent SCC behaviors remain unclear mainly due to contradictory experimental data from different researchers, the intrinsic difficulties associated with material characterization within the restricted geometry of cracks, and the complexity of the interactions between different chemical species. In this thesis, attention is focused on a single material system, AA5083 aluminum alloy, where the SCC can be made to happen quickly so that the effects of various aspects on SCC can be examined within reasonable amounts of time, for the purpose of mechanistic study. To clear the controversies about the actual SCC behaviors and to better understand the basic mechanisms of SCC, all of the three prerequisites of SCC, i.e. susceptible material, tensile stress, and corrosive environment, have been carefully examined using various materials characterization techniques. For the metallurgical aspect (susceptible material), AA5083 aluminum alloy (Al-4.4Mg-0.7Mg-0.15Cr) has been intentionally annealed at 175 °C, a process called sensitization, for a series of progressively longer treatment times. The SCC behaviors, microstructures, mechanical properties, and electrochemical properties of these differently heat treated AA5083 specimens have been characterized. It is found that the SCC incubation time decreases for longer sensitization time while the SCC initial crack growth rate increases as sensitization time becomes longer. This phenomenon is explained as a result of the development of continuous films of anodic intermetallic, Mg2Al3, known as [beta]-phase, on the grain boundaries as sensitization time increases, based on the microstructural, electrochemical, and mechanical characterizations. For the environmental aspect (corrosive environment), the SCC behaviors, as well as microstructures, of AA5083 sensitized for both 120 and 240 hours have been examined in sodium chloride (NaCl) solutions with different concentrations and pH. It has been found that both higher NaCl concentration and lower pH values lead to shorter incubation time, higher initial crack growth rate and higher total crack growth, and the SCC behaviors of the specimens that have been sensitized for 240 hours are more sensitive to environmental factors, compared with their counterparts with 120 hours sensitization condition. The fractographic analysis demonstrates the cracking mechanism is independent of the environmental factors and is still anodic dissolution based intergranular separation. The interactions between mechanical driving force (stress intensity) and chemical driving force (NaCl concentration) are also discovered. For the mechanical aspect (tensile stress), the SCC behaviors of sensitized AA5083 with different initially applied stress intensity levels have been investigated. It is found that the incubation time is a chemical process while the initial crack growth rate and total crack propagation are determined by both mechanical and chemical driving forces. The interactions between mechanical and chemical driving forces are described as a process that is dominated by chemical driving force and only assisted by mechanical driving force. Additionally, the crack mechanism is found to be anodic dissolution as well, for all different starting stress intensities. All of the above experimental efforts indicate that anodic dissolution is the dominant mechanism for SCC in sensitized AA5083 alloy."--Leaves v-vii

Download or read book The Mechanism of Stress Corrosion Cracking of Austenitic Stainless Steels written by Julius J. Harwood and published by . This book was released on 1960 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this discussion is to assess the state of our understanding concerning the factors and mechanism(s) which determine and control the susceptibility to stress-corrosion cracking of the austenitic stainless steels. The growing importance of this problem has led to a considerable amount of research, both in this country and abroad, aimed at delineating more specifically the environmental, compositional, and structural conditions involved and at elucidating the underlying mechanism for the cracking phenomenon. As a result of this research effort, a number of mechanisms have been proposed, but all appear to contain certain deficiencies in explaining certain of the characteristic features of the stress-corrosion cracking process; that is to say, unequivocal arguments cannot be presented in behalf of any of the proposed mechanisms. Possibly more to the point is the fact that few of the currently debated mechanisms have yielded critical clues which could lead to compositional or structural modifications of commercial materials to reduce or prevent the incidence of cracking. It is encouraging to note, however, that the more recent experimental evidence is developing a basis whereby critical type of experiments can be designed to differentiate clearly the mode of damage.

Download or read book Understanding the Mechanisms Involved in Chlorine Induced Stress Corrosion Cracking of Stainless Steel 304 Under a Simulated Marine Environment written by Ryan Michael Schoell and published by . This book was released on 2020 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Procedures for stress corrosion cracking characterization and interpretatation to failure safe design for high strength steels written by R. W. Judy and published by . This book was released on 1969 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Radioactive Waste Management written by and published by . This book was released on 1981 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Procedures for Stress corrosion Cracking Characterization and Interpretation to Failure safe Design for High strength Steels written by R. W Judy (Jr) and published by . This book was released on 1969 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recently evolved Ratio Analysis Diagram (RAD) procedure is a useful engineering tool for generalized assessment of the fracture resistance of high-strength steels. Failure-safe design of large complex structures also requires consideration of subcritical crack growth caused by stress-corrosion cracking (SCC). Procedures developed to incorporate SCC characterizations into the RAD concept provide a more complete analysis of a material's resistance to fracture. The SCC-Dual RAD for high-strength steels presents simplified interpretations of the critical flaw size-stress instability conditions for both slow fracture (SCC) and fast fracture of these materials. (Author).

Download or read book Summaries of Projects Completed in Fiscal Year written by and published by . This book was released on with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Summaries of Projects Completed written by National Science Foundation (U.S.) and published by . This book was released on with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface characterization to determine contributing factors in stress corrosion cracking written by I. J. Muir and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of the Corrosion Behavior of the Carbon Steel Liner in Hanford Site Single shell Tanks written by and published by . This book was released on 1994 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Six safety initiatives have been identified for accelerating the resolution of waste tank safety issues and closure of unreviewed safety questions. Safety Initiative 5 is to reduce safety and environmental risk from tank leaks. Item d of Safety Initiative 5 is to complete corrosion studies of single-shell tanks to determine failure mechanisms and corrosion control options to minimize further degradation by June 1994. This report has been prepared to fulfill Safety Initiative 5, Item d. The corrosion mechanisms that apply to Hanford Site single-shell tanks are stress corrosion cracking, pitting/crevice corrosion, uniform corrosion, hydrogen embrittlement, and microbiologically influenced corrosion. The corrosion data relevant to the single-shell tanks dates back three decades, when results were obtained from in-situ corrosion coupons in a few single-shell tanks. Since that time there have been intertank transfers, evaporation, and chemical alterations of the waste. These activities have changed the character and the present composition of the waste is not well characterized. All conclusions and recommendations are made in the absence of relevant laboratory experimental data and tank inspection data. The report attempts to identify the failure mechanisms by a literature survey of carbon steel data in environments similar to the single-shell tank wastes, and by a review of the work performed at the Savannah River Site where similar wastes are stored in similar carbon steel tanks. Based on these surveys, and in the absence of data specific to Hanford single-shell tanks, it may be concluded that the single-shell tanks identified as leakers failed primarily by stress corrosion cracking due to the presence of high nitrate/low hydroxide wastes and residual stresses. In addition, some failures may be attributed to pitting under crevices in low hydroxide locations.