Download or read book Crack Initiation and Growth Behavior at Corrosion Pit in 7075 T6 High Strength Aluminum Alloy written by Eric M. Hunt (2ND LT, USAF) and published by . This book was released on 2013 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Critical Corrosion Pit Depth for Fatigue Crack Initiation in 2024 T3 6061 T6 and 7075 T6 Aluminum Alloys written by William G. King (Jr) and published by . This book was released on 2006 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scope and method of study. Study the effects of corrosion pitting of 2024-T3, 6061-T6 and 7075-T6 aluminum alloys in 1.6 mm (0.063 inch) sheet thickness and determine the critical pit depth required for a fatigue crack to initiate. The corrosion pitting was accomplished using a 3.5% NaCl solution with hydrogen peroxide added as an accelerant. The pitting specimens were fatigue cycled in one-way bending until failure and the cycles to failure recorded. The specimens were examined with a metallurgical microscope, using the focus method of ASTM G46 to determine pitting depth.

Download or read book Stress corrosion Cracking of Aluminum Alloys written by F. H. Haynie and published by . This book was released on 1966 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report deals with the stress-corrosion cracking of aluminum alloys, and it represents an effort by DMIC to expand on the information contained in DMIC Memorandum 202, 'Stress-Corrosion Cracking of Aluminum Alloys', dated February 15, 1965. DMIC Report 228 begins by presenting a comprehensive definition of stress-corrosion cracking. This is followed by sections dealing with (1) the historical development and growth in awareness of the problem, (2) the mechanisms involved, and (3) the theory of stress-corrosion cracking. A section on experimental techniques is presented. These techniques include test methods used to determine the susceptibility of alloys to stress-corrosion cracking, as well as more refined methods of studying the fundamental mechanisms of the problem. Different evaluation methods, applicable to obtaining the different objectives of stress-corrosion testing, are also presented. All of the foregoing serve as background to the sections on stress-corrosion-cracking behavior of aluminum alloys and preventive measures. (Author).

Download or read book The Combined Effects of Prior corrosion and Aggressive Chemical Environments on Fatigue Crack Growth Behavior in Aluminum Alloy 7075 T651 written by Thomas Brian Mills and published by . This book was released on 1997 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress corrosion Cracking in High Strength Steels and in Titanium and Aluminum Alloys written by Benjamin Floyd Brown and published by . This book was released on 1972 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Growth of Small Corrosion Fatigue Cracks in Alloy 2024 written by Robert S. Piascik and published by . This book was released on 1993 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Microstructure on Pit to Crack Transition of 7075 T6 Aluminum Alloy written by Kimberli Jones and published by . This book was released on 2006 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this research was to gain an increased understanding of how microstructure influences pit growth, pit-to-crack transition, and critical crack propagation to fracture. Two thicknesses of 7075-T6 aluminum alloy were etched and subjected to corrosion fatigue in a 3.5 % sodium chloride environment. 7075-T6 aluminum alloy is of particular interest to the aging aircraft community, as this alloy has been used extensively on wing and fuselage structures for both military and commercial aircraft in the past. Testing was interrupted at various intervals to obtain information on pit generation, growth, and potential cracking. Results indicated that microstructure has a significant influence on pit-to-crack transition and fatigue crack propagation. Short cracks (

Download or read book The Growth of Small Corrosion Fatigue Cracks in Alloy 2024 written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-12 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The corrosion fatigue crack growth characteristics of small surface and corner cracks in aluminum alloy 2024 is established. The damaging effect of salt water on the early stages of small crack growth is characterized by crack initiation at constituent particle pits, intergranular microcracking for a less than 100 micrometers, and transgranular small crack growth for a micrometer. In aqueous 1 percent NaCl and at a constant anodic potential of -700 mV(sub SCE), small cracks exhibit a factor of three increase in fatigue crack growth rates compared to laboratory air. Small cracks exhibit accelerated corrosion fatigue crack growth rates at low levels of delta-K (less than 1 MPa square root of m) below long crack delta-K (sub th). When exposed to Paris regime levels of crack tip stress intensity, small corrosion fatigue cracks exhibit growth rates similar to that observed for long cracks. Results suggest that crack closure effects influence the corrosion fatigue crack growth rates of small cracks (a less than or equal to 100 micrometers). This is evidenced by similar small and long crack growth behavior at various levels of R. Contrary to the corrosion fatigue characteristics of small cracks in high strength steels, no pronounced chemical crack length effect is observed for Al by 2024 exposed to salt water. Piascik, Robert S. and Willard, Scott A. Langley Research Center RTOP 538-02-10-01

Download or read book Environmentally Influenced Near Threshold Fatigue Crack Growth in 7075 T651 Aluminum Alloy written by HC. Sanders and published by . This book was released on 2000 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The near-threshold fatigue crack growth behavior of the 7075-T651 aluminum alloy was studied in laboratory air, vacuum, and an aqueous 3.5% NaCl solution. Results indicate that a rising stress ratio (R) enhanced the near-threshold fatigue crack growth by increasing the crack growth rate (da/dN) and decreasing the threshold stress intensity range (?Kth) in both laboratory air and aqueous 3.5% NaCl solution. However, the reverse was observed in vacuum. It was also noticed that the near-threshold fatigue crack growth resistance was greatest in vacuum, intermediate in aqueous 3.5% NaCl solution, and lowest in laboratory air. Conversely, the crack growth rate at given values of AK were shown to be greatest in laboratory air, less in 3.5% NaCl solution, and lowest in vacuum. In both laboratory air and aqueous 3.5% NaCl solution, ?Kth, initially decreased with increasing R until a critical stress ratio of Rc = 0.5 was reached, which it then leveled off or decreased slightly. The ?Kth values for these two environments appear to converge at a higher R. On the other hand, in vacuum, the ?Kth, increased linearly with increasing R. In addition, at lower R, a greater resistance to near-threshold fatigue crack growth was detected in aqueous 3.5% NaCl solution than in laboratory air. This is presumably attributed to crack closure that has been induced by accumulation of corrosion product in the crack-tip.

Download or read book Effect of Stress Ratio on Fatigue crack Growth in 7075 T6 and 2024 T3 Aluminum alloy Specimens written by C. M. Hudson and published by . This book was released on 1969 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stress ratio effects on fatigue crack growth in sheet aluminum alloys.

Download or read book Corrosion Control in the Aerospace Industry written by Samuel Benavides and published by Elsevier. This book was released on 2009-01-21 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion control in the aerospace industry has always been important, but is becoming more so with the ageing of the aircraft fleet. Corrosion control in the aerospace industry provides a comprehensive review of the subject with real-world perspectives and approaches to corrosion control and prevention. Part one discusses the fundamentals of corrosion and the cost of corrosion with chapters on such topics as corrosion and the threat to aircraft structural integrity and the effect of corrosion on aluminium alloys. Part two then reviews corrosion monitoring, evaluation and prediction including non-destructive evaluation of corrosion, integrated health and corrosion monitoring systems, modelling of corrosion and fatigue on aircraft structures and corrosion control in space launch vehicles. Finally, Part three covers corrosion protection and prevention, including chapters which discuss coating removal techniques, novel corrosion schemes, greases and their role in corrosion control and business strategies in fleet maintenance. With its distinguished editor and team of expert contributors, Corrosion control in the aerospace industry is a standard reference for everyone involved in the maintenance and daily operation of aircraft, as well as those concerned with aircraft safety, designers of aircraft, materials scientists and corrosion experts. Discusses the fundamentals of corrosion and the cost of corrosion to the aerospace industry Examines the threat corrosion poses to aircraft structural integrity and the effect of corrosion on the mechanical behaviour of aircraft Reviews methods for corrosion monitoring, evaluation and prediction examining both current practices and future trends

Download or read book Materials Science And Engineering Proceedings Of The 2nd Annual International Workshop Iwmse 2016 written by Roman Szewczyk and published by #N/A. This book was released on 2017-06-29 with total page 1168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 2nd Annual 2016 International Workshop on Materials Science and Engineering (IWMSE 2016) was held in Guangzhou, Guangdong, China on August 12 - August 14, 2016. The main aim of IWMSE 2016 was to provide a platform for scientists and engineers, to get together to share their research findings, exchange ideas and identify the future directions of R&D in materials science.In this conference, we have received over 272 high-quality papers, however, only 160 articles are included in the proceedings, covering topics such as ceramics and glasses, amorphous materials, nanomaterials and thin layers, soft magnetic materials, biomaterials, polymers, photovoltaic materials, steels, tool materials, composites, as well as functional and smart materials.

Download or read book Metallurgy and Design of Alloys with Hierarchical Microstructures written by Krishnan K. Sankaran and published by Elsevier. This book was released on 2017-06-14 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallurgy and Design of Alloys with Hierarchical Microstructures covers the fundamentals of processing-microstructure-property relationships and how multiple properties are balanced and optimized in materials with hierarchical microstructures widely used in critical applications. The discussion is based principally on metallic materials used in aircraft structures; however, because they have sufficiently diverse microstructures, the underlying principles can easily be extended to other materials systems. With the increasing microstructural complexity of structural materials, it is important for students, academic researchers and practicing engineers to possess the knowledge of how materials are optimized and how they will behave in service. The book integrates aspects of computational materials science, physical metallurgy, alloy design, process design, and structure-properties relationships, in a manner not done before. It fills a knowledge gap in the interrelationships of multiple microstructural and deformation mechanisms by applying the concepts and tools of designing microstructures for achieving combinations of engineering properties—such as strength, corrosion resistance, durability and damage tolerance in multi-component materials—used for critical structural applications. Discusses the science behind the properties and performance of advanced metallic materials Provides for the efficient design of materials and processes to satisfy targeted performance in materials and structures Enables the selection and development of new alloys for specific applications based upon evaluation of their microstructure as illustrated in this work

Download or read book Corrosion and Corrosion fatigue Behavior of 7075 Aluminum Alloys Studied by in Situ X ray Tomography written by Tyler Stannard and published by . This book was released on 2017 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: 7XXX aluminum alloys have high strength to weight ratio and low cost. They are used in many critical structural applications including automotive and aerospace components. These applications frequently subject the alloys to static and cyclic loading in service. Additionally, the alloys are often subjected to aggressive corrosive environments such as saltwater spray. These chemical and mechanical exposures have been known to cause premature failure in critical applications. Hence, the microstructural behavior of the alloys under combined chemical attack and mechanical loading must be characterized further. Most studies to date have analyzed the microstructure of the 7XXX alloys using two dimensional (2D) techniques. While 2D studies yield valuable insights about the properties of the alloys, they do not provide sufficiently accurate results because the microstructure is three dimensional and hence its response to external stimuli is also three dimensional (3D). Relevant features of the alloys include the grains, subgrains, intermetallic inclusion particles, and intermetallic precipitate particles. The effects of microstructural features on corrosion pitting and corrosion fatigue of aluminum alloys has primarily been studied using 2D techniques such as scanning electron microscopy (SEM) surface analysis along with post-mortem SEM fracture surface analysis to estimate the corrosion pit size and fatigue crack initiation site. These studies often limited the corrosion-fatigue testing to samples in air or specialized solutions, because samples tested in NaCl solution typically have fracture surfaces covered in corrosion product. Recent technological advancements allow observation of the microstructure, corrosion and crack behavior of aluminum alloys in solution in three dimensions over time (4D). In situ synchrotron X-Ray microtomography was used to analyze the corrosion and cracking behavior of the alloy in four dimensions to elucidate crack initiation at corrosion pits for samples of multiple aging conditions and impurity concentrations. Additionally, chemical reactions between the 3.5 wt% NaCl solution and the crack surfaces were quantified by observing the evolution of hydrogen bubbles from the crack. The effects of the impurity particles and age-hardening particles on the corrosion and fatigue properties were examined in 4D.

Download or read book Effect of Specimen Thickness on Fatigue crack growth Behavior and Fracture Toughness of 7075 T6 and 7178 T6 Aluminum Alloys written by Charles Michael Hudson and published by . This book was released on 1973 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Mean Stress and Environment on Corrosion Fatigue Behavior of 7075 T6 Aluminum written by L. V. Corsetti and published by . This book was released on 1973 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Axial fatigue tests were performed on a 7075-T6 aluminum alloy in tension-compression and under superimposed positive mean stresses in dry air and in aqueous 0.5N NaCl solution. Both corrosive environments and positive mean stresses resulted in lower fatigue lives but no interaction between these variables was observed. Crack initiation in air occurred at electropolish pits at inclusion/alloy interfaces and propagated primarily in a Stage I (crystallographic) mode. A model for environment assisted cracking is presented which suggests that hydrogen induced cleavage is responsible for the degradation in fatigue properties of this alloy. (Modified author abstract).

Download or read book Corrosion Fatigue Crack Propagation Rates in Commercial 7075 and P M X7091 Aluminum Alloys written by M. Kumar and published by . This book was released on 1983 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recently developed powder metallurgy (P/M) alloy X7091 (formerly CT91) has strength characteristics similar to ingot metallurgy (I/M) 7000 series alloys. However, its stress corrosion cracking resistance has been reported to be far superior to the conventional ingot-processed alloys. This suggests that P/M alloy X7091 may have far better corrosion fatigue behavior than I/M 7075-T651. Fatigue crack growth rates between 2.5 x 10-8 and 2.5 x 10-6 m/cycle (10-6 and 10-4 in./cycle) were measured for specimens in both the S-T and T-L orientations. In order to determine the effect of environment on the fatigue crack growth rates, tests were conducted in both an innocuous and an aggressive environment (R = 0.5; f = 0.2 Hz). Since it is known that the fatigue crack growth rates of aluminum alloys are sensitive to small amounts of water vapor, gaseous nitrogen with a dew point of -60°C (-75°F) was chosen as the innocuous environment. An aerated 31⁄2% NaCl solution was used as the corrosive environment.