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 Crack Closure Effects on the Growth of Small Surface Cracks in Titanium Aluminum Alloys written by JM. Larsen and published by . This book was released on 1988 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Among other factors, the reported failure of linear elastic fracture mechanics to correlate the growth rates of large and very small fatigue cracks has been attributed to microstructural and crack closure effects. These two factors have been examined in experiments on three titanium-rich Ti-Al alloys, which display significant differences in plastic slip character ranging from homogeneous wavy slip to extremely heterogeneous planar slip. The variation in slip character has a dramatic effect on the level of roughness induced crack closure, which in turn, strongly influences the growth rate behavior of large fatigue cracks. In the present project the behavior of small fatigue surface cracks in these materials was investigated using two specialized experimental techniques. A computer-controlled photomicroscopic system was employed to monitor surface crack length directly, and an automated laser interferometric technique was used independently to determine crack length and to measure the development of crack closure. Although slip character has a strong influence on the propagation of large cracks, the present findings indicate that there is a minimal effect of slip character on the growth of small fatigue cracks. Direct crack opening displacement measurements indicate that this is largely because of a transient development of crack closure in the small cracks. For the materials tested, the crack depth required to fully develop crack closure ranged from 5 to 13 times the mean distance between grain boundaries. Above this crack size, data from small surface cracks and large cracks in C(T) specimens were well consolidated by the linear-elastic parameter ?K.
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 261 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Closure on the Fatigue Crack Growth of Small Surface Cracks in a High Strength Titanium Alloy written by Jira, JR. and published by . This book was released on 1988 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue crack growth experiments were conducted on surface flaws in a high-strength titanium alloy. Surface crack lengths in the range 50-?m to 8 mm were investigated under both increasing and decreasing ?K conditions. Crack length and closure loads were determined from load-displacement data obtained with the aid of a laser interferometric displacement gage, which has resolution capability at 0.01 ?m. Stress ratios of 0.1, 0.5, and -1.0 and net-section stress levels from 0.2 to 0.9 of yield stress were utilized. The applied stress intensity factor range, ?K, correlated crack-growth-rate data for R = 0.1 and R = -1, but all R = 0.5 data fell along a separate band. The effective stress intensity factor range ?Keff determined from closure data, consolidated most of the data into a single band, but some small-crack data fell outside the band. Fracture surface roughness and plasticity were concluded to be the primary features contributing to crack closure.
Download or read book The Effects of Slip Character and Crack Closure on the Growth of Small Fatigue Cracks in Titanium aluminum Alloys written by James Milligan Larsen and published by . This book was released on 1987 with total page 261 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanics of Fatigue Crack Closure written by Wolf Elber and published by ASTM International. This book was released on 1988 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The effect of slip character and crack closure on the growth of small fatigue cracks in titanium aluminum alloys written by James Larsen and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Small crack Effects in High strength Aluminum Alloys written by J. C. Newman (Jr) and published by . This book was released on 1994 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crack closure and Crack growth Measurements in Surface flawed Titanium Alloy Ti 6Al 4V written by Elber Wolf and published by . This book was released on 1975 with total page 22 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 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 Fatigue Crack Propagation in Metals and Alloys written by Ulrich Krupp and published by John Wiley & Sons. This book was released on 2007-04-09 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive overview of the whole field of fatigue and fracture of metallic materials covers both the theoretical background and some of the latest experimental techniques. It provides a summary of the complex interactions between material microstructure and cracks, classifying them with respect to the overall damage process with a focus on microstructurally short cracks and dynamic embrittlement. It furthermore introduces new concepts for the numerical treatment of fatigue microcrack propagation and their implementation in fatigue-life prediction models.This comprehensive overview of the whole field of fatigue and fracture of metallic materials covers both the theoretical background and the latest experimental techniques. It provides a summary of the complex interactions between material microstructure and cracks, classifying them with respect to the overall damage process. It furthermore introduces new concepts for the numerical treatment of fatigue microcrack propagation and their implementation in fatigue-life prediction models.
Download or read book Small Fatigue Cracks written by K.S. Ravichandran and published by Elsevier. This book was released on 1999-09-30 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the fully peer-reviewed papers presented at the Third Engineering Foundation Conference on Small Fatigue Cracks, held under the chairmanship of K.S. Ravichandran and Y. Murakami during December 6-11, 1998, at the Turtle Bay Hilton, Oahu, Hawaii. This book presents a state-of-the-art description of the mechanics, mechanisms and applications of small fatigue cracks by most of the world's leading experts in this field. Topics ranging from the mechanisms of crack initiation, small crack behavior in metallic, intermetallic, ceramic and composite materials, experimental measurement, mechanistic and theoretical models, to the role of small cracks in fretting fatigue and the application of small crack results to the aging aircraft and high-cycle fatigue problems, are covered.
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 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Small crack Test Methods written by James M. Larsen and published by ASTM International. This book was released on 1992 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews the most recent methods for testing small cracks in a variety of materials, providing detailed quantitative information on necessary procedures for data acquisition. Emphasizes the characterization of small, three-dimensional fatigue cracks, initiated either naturally or artificially. The ei
Download or read book On the Initiation and Growth of Small Fatigue Cracks in Gamma based Titanium Aluminides written by Jamie Joseph Kruzic and published by . This book was released on 1998 with total page 134 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 702 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:
