Download or read book Effect of Stress Ratio on Fatigue Crack Growth and Mode of Fracture in 2024 T4 and 7075 T6 Aluminum Alloys in the Low cycle Range written by D. Y. Wang and published by . This book was released on 1966 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigation was conducted at minimum-to-maximum stress ratios R of -2.5, -2.0, -1.5, -1.0, 0.0 and 0.6. It was observed that the fracture mechanism of low-cycle fatigue involves Stage II fatigue crack growth which is characterized by the development of ductile striations and two essential types of secondary fracture surfaces. It is shown that ductile fatigue crack growth, which involves two types of ductile striations, is governed by the local irreversible plastic deformation at the crack tip in both alloys. The most important mode of secondary crack growth in 2024-T4 aluminum is the brittle fracture or decohension of the constituent particles ahead of the crack tip and the subsequent growth of the interior cracks toward the main crack. The size of the plastic zone at the crack tip appears to determine the degree of influence of this mode of fracture on overall crack growth rate. In 7075-T6, the dominant mode of secondary crack growth is the quasi-cleavage fracture of the matrix. The frequency of occurrence of these two modes of secondary crack growth increases with the stress ratio, i.e., with increasing mean stress. The change in the modes of crack growth as we change from low to high mean stress contributes to the relative differences in fatigue strength of the two materials at various stress ratios.
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 Technical Abstract Bulletin written by and published by . This book was released on with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Abstracts of AF Materials Laboratory Reports written by Air Force Materials Laboratory (U.S.) and published by . This book was released on 1968 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technical reports published by the Air Force Materials Laboratory during the period 1 January 1967-31 December 1967 are abstracted herein and indexed by branches of the laboratory, technical subject matter, investigator, project monitor and contractor. Reports on research conducted by the Air Force Materials Laboratory personnel as well as that conducted on contract are included.
Download or read book Astm Stp 449 Copy righted written by and published by ASTM International. This book was released on with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aerospace Structural Metals Handbook written by and published by . This book was released on 1989 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Propagation in 2024 T3 and 7075 T6 Aluminum Alloys at High Stresses written by Robert G. Dubensky and published by . This book was released on 1971 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth with Negative Stress Ratio Following Single Overloads in 2024 T3 and 7075 T6 Aluminum Alloys written by DK. Chen and published by . This book was released on 1976 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modified pre-cracked compact specimens of 2024-T3 and 7075-T6 aluminum alloys were subjected to four different overload patterns followed by subsequent constant-amplitude steady-state loading with R=Plmin/lmax equal to 0, -1/2, -1, and -2. The overload patterns were tension, compression-tension, tension-compression, and compression. Cyclic loading with negative stress ratio, R, drastically reduced crack-growth retardation. The higher the negative R ratio the greater the reduction in retardation. Overload ratios, OLR =Phmax/Plmax, ranging from 2.0 to 3.0 were used. For compression overloads, the OLR ranged from -2.0 to -4.0. High compression overloading was detrimental and dependent upon subsequent R ratio loading. Substantial fracture surface abrasion near the mid-thickness occurred for higher negative R ratios. Striations were not readily found in this region, however, they were quite evident near the edges, which indicated crack closure was greater near the mid-thickness. The 2024-T3 gave better crack growth life than 7075-T6 in some loading conditions, while the opposite was true for other loadings. The results indicate negative R ratio must be considered in retardation models and that retardation life cannot be modeled based solely on overload plastic zone sizes.
Download or read book Electron Fractography Handbook written by and published by . This book was released on 1976 with total page 2190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book World Aluminum Abstracts written by and published by . This book was released on 1973 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Stress Ratio During Crack Propagation and Fatigue for 2024 T3 and 7075 T6 Aluminum written by K. Walker and published by . This book was released on 1970 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: An effective stress, ? ̄ = ?max1-m??m where m is assumed to be a material constant, is shown to predict the effect of stress ratio on crack propagation and fatigue life for two aluminum alloys. Simple approximations of notch stress and strain using Neuber's notch rule are introduced to extend the predictions of stress-ratio effects to inelastic notch behavior.
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 Aerospace Structural Metals Handbook written by Belfour Stulen, Inc. Mechanical Properties Data Center and published by . This book was released on 1970 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Stress Ratio on Fatigue Crack Growth Rate at Notched Hole in 7075 T6 Aluminum Alloy Under Biaxial Fatigue written by Reja Alshahrani (Capt., RSAF.) and published by . This book was released on 2016 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Stress Ratio on Fatigue crack Growth in 7075 T6 and 2024 T3 Aluminum alloy Specimens written by C. Michael Hudson and published by . This book was released on 1969 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Slip Character and Crack Closure on the Growth of Small Fatigue Cracks in Titanium aluminium Alloys written by James M. Larsen and published by . This book was released on 1990 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was performed to study the effects of slip character and crack closure on the propagation of small fatigue cracks in titanium- aluminum alloys. The materials examined were solution-treated Ti-4Al and Ti-8Al, as well as aged Ti-8Al. The propagation of naturally initiated surface cracks of depths as small as 25 micrometers was compared with the behavior of large through-thickness cracks. An extensometer was used to monitor crack closure throughout the large crack tests, and the closure behavior of the small cracks was measured using a computerized laser interferometric displacement gage having a displacement resolution of 0.01 micrometer. The measurements of crack closure were used to compute an effective stress intensity factor range. In all three alloys and for all test conditions, which included a range of stress levels and stress ratios, small cracks propagated faster than large cracks subjected to an equivalent Delta K, and the small cracks propagated under conditions that were significantly below the large-crack threshold, Delta K(th). Although the character and distribution of slip in Ti-Al alloys may have a dramatic influence on fatigue crack initiation and on the propagation of large cracks, this effect was minimal for small cracks.
Download or read book Metals Abstracts written by and published by . This book was released on 1995 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
