Download or read book The Effects of Corrosion and Cathodic Charging on Fatigue Crack Propagation in 7075 T651 Aluminum written by Stephen E. LeBeau and published by . This book was released on 1978 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion fatigue crack propagation tests were performed on 7075 aluminum in dry argon, and solutions of NaCl and Na2SO4 under free corrosion conditions and under applied polarization. Bulk solution pH and oxygen level were also varied. Tests were also conducted in air after pre-exposure to an aggressive environment. Results indicate that both aqueous solutions appreciably increase fatigue crack growth rates. The Cl-ion generally produces the greatest increase in fatigue crack growth rate. Results indicate that adjusting bulk solution pH and decreasing the oxygen level can accelerate fatigue cracking. The magnitude of these effects is a function of the electrochemical conditions and the integrity of the oxide film at the crack tip.

Download or read book The Impact of Corrosion on Fatigue Crack Propagation in 7075 T6 Aluminum Alloy written by Tuong Tom Quang Vu and published by . This book was released on 1999 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Corrosion Temperature and Overload on Fatigue Crack Growth Rate Retardation in 7075 T651 Aluminum Alloy written by Mikio Scot Oshiro and published by . This book was released on 2000 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanisms of Corrosion Fatigue Crack Propagation in Aluminum 7075 T651 written by Thomas Steven Sparks and published by . This book was released on 1980 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book The Effect of Water Vapor on Fatigue Crack Growth in 7475 t651 Aluminum Alloy Plate written by and published by . This book was released on 1982 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Corrosion Fatigue Crack Propagation in Aluminum Alloys Part I Effect of Cyclic Stress Wave Form on Corrosion Fatigue Crack Propagation in Al Zn Mg Alloys Part II Mechanisms of Corrosion Fatigue Crack Propagation in Al Zn Mg Alloys written by Ronald J. Selines and published by . This book was released on 1972 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report is divided into 2 parts. In part one, fatigue crack growth rates of a 7075 type aluminum alloy were measured as a function of environment, frequency, stress wave form, alloy chemistry, and thermomechanical treatment. Results are discussed. Part 2 discusses corrosion fatigue crack propagation tests which were performed on commercial 7075 alloys. Testing was done in a 3.5% sodium chloride solution under constant impressed potential and under reversed anodic-cathodic current conditions.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1977 with total page 1006 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Corrosion fatigue Technology written by and published by ASTM International. This book was released on 1978 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Environmental Corrosion fatigue Behavior of Aluminum Alloys written by D. N. Williams and published by . This book was released on 1970 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of environment on fatigue behavior are quite intimately related to such test variables as stress intensity, cyclic frequency, and temperature. The effect of these variables has been shown to be quite complex. However, a consistent pattern of behavior is beginning to emerge which, it is hoped, will lead to a considerably changed understanding of the corrosion-fatigue process. It is considered probable that an increased understanding of the corrosion-fatigue process will also contribute measureably to an improved understanding of general fatigue processes. Material variables such as composition, directionality of properties, and microstructure, have important effects on corrosion-fatigue behavior of aluminum alloys. However, it appears that these variables, at least in gaseous environments, may be important largely because of their effects on the mechanical behavior of aluminum alloys. On the other hand, studies in seawater suggest that these variables become increasingly important as the corrosive nature of the environment increases. This memorandum discusses in detail the effects of both test variables and material variables on corrosion fatigue. In addition, current theories of corrosion-fatigue mechanisms are outlined, and several methods of preventing corrosion fatigue are suggested. (Author).

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 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 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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 1142 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress corrosion of the Aluminum Alloy 7075 t651 in Organic Liquids written by R. P. M. Procter and published by . This book was released on 1968 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: It was shown that stress-corrosion cracks will propagate from a fatigue-precrack in 7075-T651 aluminum alloy exposed to various organic environments; stress-corrosion cracks will not, however, initiate in smooth specimens. Evidence is presented which indicates that the crack propagation is probably not due to traces of water absorbed in the oxide film at the crack tip or in the environments. The stress-corrosion crack growth rate was measured in ethanol and carbon tetrachloride as a function of the plane-strain stress-intensity factor K. The results of a fractographic analysis of the fracture surfaces are described. Evidence is presented to show that some limited dissolution of aluminum in the environments occurs and it is suggested that, as with aqueous stress-corrosion of aluminum alloys, an electrochemical reaction is involved in the cracking. (Author).

Download or read book Environmentally Influenced Near Threshold Fatigue Crack Growth in 7075 T651 Aluminum Alloy written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The near-threshold fatigue crack growth behavior of a 7075-T651 aluminum alloy was studied in laboratory air, vacuum, and an aqueous 3.5% NaCl solution. Results obtained indicate that raising the stress ratio R enhanced the near-threshold fatigue crack growth with a greater crack growth rate da/dN and smaller threshold stress intensity range deltaK(th) in laboratory air and an aqueous 3.5% NaCl solution. However, the reverse was observed in vacuum. The near-threshold fatigue crack growth was most sluggish with the smallest da/dN and greatest deltaK(th) values in vacuum, intermediate with an intermediate da/dN and deltaK(th) in the aqueous 3.5% NaCl solution, and fastest with the greatest da/dN and smallest deltaK(th) values in laboratory air. In laboratory air and aqueous 3.5% NaCl solution deltaK(th) initially decreased with increasing R until a value of 0.5 was reached, and then leveled off or decreased slightly. The detlaK(th) values for these two environments appear to converge at a higher R. On the other hand, in vacuum, the deltaK(th) increased linearly with increasing R. In addition, at lower R, a greater resistance to near-threshold fatigue crack growth was detected in the aqueous 3.5% NaCl solution than in laboratory air. This is attributable to crack closure, induced by corrosion product at the crack tip.