Download or read book Evolution of Fatigue Crack Growth and Fracture Behavior in Gamma Titanium Aluminide Ti 43 5Al 4Nb 1Mo 0 1B TNM Forgings written by 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 High Temperature Fracture and Fatigue Crack Growth of a gamma based Titanium Aluminide written by Aindrea Leigh McKelvey and published by . This book was released on 1996 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Growth Behavior of Titanium Aluminide Ti 25Al 25Nb written by SJ. Balsone and published by . This book was released on 1993 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fatigue crack growth rate of an orthorhombic + beta titanium aluminide, nominally Ti-25Al-25Nb, was studied as a function of temperature (25 to 750°C), environment (air and vacuum), frequency (0.001 to 1.0 Hz), and superimposed hold times (1 to 1000 s) under computer-controlled constant Kmax testing conditions. In addition, fatigue crack growth rates from the near-threshold region to rates greater than approximately 10-7 m/cycle were determined at room and elevated temperatures. Results show that the fatigue crack growth rate exhibits a combination of cycle- and time-dependent behavior and is sensitive to environment over the entire temperature range. At elevated temperature, crack growth per cycle is found to increase with decreasing frequency in both laboratory air and vacuum, suggesting a contribution from environmentally assisted crack growth. Growth rates in vacuum are as much as an order of magnitude lower than those obtained in air. Further, hold times of increasing duration are found to slightly decrease and then increase the crack growth rate at elevated temperature. At elevated temperatures, crack growth behavior appears to be a complex interaction of environmental degradation at the crack tip, crack-tip blunting due to creep, and cyclic fatigue (resharpening of the crack tip). An attempt was made to correlate the observed fatigue crack growth rates with the mechanism, or mechanisms, of fracture. The crack growth characteristics were compared with those of the alpha-2 titanium aluminide, Ti-24Al-11 Nb, and a conventional high-temperature titanium alloy, Ti-1100.

Download or read book Evaluation of a Threshold based Model of Fatigue in Gamma Titanium Aluminide Following Impact Damage written by Trevor S. Harding and published by . This book was released on 2000 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Growth Characteristics of Thin Sheet Titanium Alloy Ti 6 2 2 2 2 written by and published by . This book was released on 2001 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of O2 H2O and N2 on the Fatigue Crack Growth Behavior of an Alpha Beta Titanium Alloy at 24 C and 177 C written by Stephen W. Smith and published by . This book was released on 2001 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Subcritical Fatigue Crack Growth in Gamma Titanium Aluminides written by and published by . This book was released on 2004 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our titanium aluminide alloy was readily heat treated to a fully lamellar state by holding at 1345C for 1.5 hours and furnace cooling resulting in a grain size of 330 muon m. The yield stress, ultimate stress, and total elongation were 315MPa, 465MPa, and 0.46% respectively. The fully lamellar microstructure shows significant work hardening. No long cracks initiated at R=0.1 and variation max=300MPa with up to 1.4 million cycles.

Download or read book Crack Growth of a Titanium Aluminide Alloy Under Thermal Mechanical Fatigue written by David G. Burgess and published by . This book was released on 1988 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: New materials must be developed in order to increase the operating temperature of Air Force gas turbines. One of the materials under consideration is a titanium-aluminide alloy, Ti3Al1. Before this material can be used, its behavior under combined thermal-mechanical fatigue (TMF) conditions must be understood. To understand this behavior, three 315-649 C TMF test and one 649 C isothermal fatigue test with load hold time were conducted. Crack growth data from these tests were compared with each other as well as with crack growth data from four previous TMF and isothermal fatigue tests of the same material. Keywords: Metal fatigue; Crack propagation; Fracture mechanics; Physical metallurgy. (kt/jes).

Download or read book Fatigue Damage Crack Growth and Life Prediction written by F. Ellyin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue failure is a multi-stage process. It begins with the initiation of cracks, and with continued cyclic loading the cracks propagate, finally leading to the rupture of a component or specimen. The demarcation between the above stages is not well-defined. Depending upon the scale of interest, the variation may span three orders of magnitude. For example, to a material scientist an initiated crack may be of the order of a micron, whereas for an engineer it can be of the order of a millimetre. It is not surprising therefore to see that investigation of the fatigue process has followed different paths depending upon the scale of phenomenon under investigation. Interest in the study of fatigue failure increased with the advent of industrial ization. Because of the urgent need to design against fatigue failure, early investiga tors focused on prototype testing and proposed failure criteria similar to design formulae. Thus, a methodology developed whereby the fatigue theories were proposed based on experimental observations, albeit at times with limited scope. This type of phenomenological approach progressed rapidly during the past four decades as closed-loop testing machines became available.

Download or read book An Investigation of the Fatigue Crack Growth and Fracture Behavior of Ti 6Al 4V written by Michael Alan Foster and published by . This book was released on 1998 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Life and Crack Growth Prediction Methodology written by J. C. Newman (Jr) and published by . This book was released on 1993 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Growth Characteristics of Thin Sheet Titanium Alloy Ti 6 2 2 2 2 written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-31 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue crack growth rates of Ti 6-2-2-2-2 as a function of stress ratio, temperature (24 or 177 C), tensile orientation and environment (laboratory air or ultrahigh vacuum) are presented. Fatigue crack growth rates of Ti 6-2-2-2-2 are also compared with two more widely used titanium alloys (Timetal 21S and Ti 6Al-4V). The fatigue crack growth rate (da/dN) of Ti 6-2-2-2-2 in laboratory air is dependent upon stress ratio (R), particularly in the near-threshold and lower-Paris regimes. For low R (less than approximately 0.5), da/dN is influenced by crack closure behavior. At higher R (> 0.5), a maximum stress-intensity factor (K(sub max)) dependence is observed. Fatigue crack growth behavior is affected by test temperature between 24 and 177 C. For moderate to high applied cyclic-stress-intensity factors (delta-K), the slope of the log da/dN versus log delta-K curve is lower in 177 C laboratory air than 24 C laboratory air. The difference in slope results in lower values of da/dN for exposure to 177 C laboratory air compared to room temperature laboratory air. The onset of this temperature effect is dependent upon the applied R. This temperature effect has not been observed in ultrahigh vacuum. Specimen orientation has been shown to affect the slope of the log da/dN versus log delta-K curve in the Paris regime.Smith, Stephen W. and Piascik, Robert S.Langley Research CenterCRACK PROPAGATION; FATIGUE (MATERIALS); TITANIUM ALLOYS; CORROSION; STRESS RATIO; TEMPERATURE EFFECTS; CRACK CLOSURE; STRESS INTENSITY FACTORS

Download or read book Investigation of Fatigue Crack Growth in Ti 8A1 1Mo 1V duplex annealed Specimens Having Various Widths written by C. M. Hudson and published by . This book was released on 1967 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Variable Amplitude Fatigue Crack Growth in Titanium Alloy Ti 4Al 4Mo 2Sn 0 5Si IMI 550 written by C. M. Ward-Close and published by . This book was released on 1988 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study has been made of fatigue crack growth behaviour in the titanium alloy (Ti-4Al-4Mo-2Sn-0.5Si) (IMI 550)), subject to single tensile overloads and the FALSTAFF flight simulation loading spectrum. Fatigue overloads were found to produce crack growth rate acceleration, followed by delayed retardation. The transient changes in crack growth rates were associated with large changes in crack closure immediately behind the crack tip. For both single overloads and flight simulation loading, the greatest load-interaction effects were at the lowest load amplitudes. Microstructure had only a slight influence on load-interaction effects associated with single tensile overloads. Great Britain. (jes).

Download or read book The Fatigue Crack Growth Behavior of Ti 24A1 11Nb as a Function of Temperature and Load Ratio written by Richard Joseph Bernard and published by . This book was released on 1991 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Growth Behavior of Two Titanium Alloys at Room and Elevated Temperature written by Todd P. Albertson and published by . This book was released on 1996 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of O2 H2o and N2 on the Fatigue Crack Growth Behavior of an Alpha Beta Titanium Alloy at 24 C and 177 C written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-11 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: To study the effects of atmospheric species on the fatigue crack growth behavior of an a+B titanium alloy (Ti 6-2-2-2-2) at room temperature and 177 C, fatigue tests were performed in laboratory air, ultrahigh vacuum, and high purity water vapor, oxygen, nitrogen and helium at various partial pressures. Accelerated fatigue crack growth rates in laboratory air compared to ultrahigh vacuum are linked to the damaging effects of both water vapor and oxygen. Observations of the fatigue crack growth behavior in ultrahigh purity environments, along with surface film analysis using X-ray photoelectron spectroscopy (XPS), suggest that multiple crack-tip processes govern the damaging effects of air. Three possible mechanisms are proposed: 1) at low pressure (less than 10(exp -1) Pa), accelerated da/dN is likely due to monolayer adsorption on crack-tip surfaces presumably resulting in decreased bond strengths at the fatigue crack tip, 2) for pressures greater than 10(exp -1) Pa, accelerated da/dN in oxygen may result from oxidation at the crack tip limiting reversible slip, and 3) in water vapor, absorption of atomic hydrogen at the reactive crack tip resulting in process zone embrittlement.Smith, Stephen W. and Piascik, Robert S.Langley Research CenterFATIGUE TESTS; FATIGUE (MATERIALS); CRACK PROPAGATION; TITANIUM ALLOYS; EMBRITTLEMENT; ATMOSPHERIC COMPOSITION; X RAY SPECTROSCOPY; WATER VAPOR; ULTRAHIGH VACUUM; PHOTOELECTRON SPECTROSCOPY