Download or read book The Effects of Stress Ratio and Elevated Temperature on Near threshold Fatigue Crack Growth of Titanium 8A1 1Mo 1V written by Jennifer Heine and published by . This book was released on 1987 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1970 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Ti 8A1 1Mo 1V Alloy written by R. A. Wood and published by . This book was released on 1965 with total page 120 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 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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1975 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Fatigue Crack Growth of Two Advanced Titanium Alloys at Room and Elevated Temperature written by TP. Albertson and published by . This book was released on 1997 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper provides fatigue crack growth information at low crack growth rates for two sheet titanium alloys: ?-21S, a ? alloy, and Ti-62222, an ? + ? alloy. Room (25°C) and elevated temperature (175°C) fatigue crack growth tests at two different stress ratios, R = 0.1 and 0.5, were performed. Effects of temperature and stress ratio were evaluated in order to study the complex interaction between fatigue, environment, and loading conditions. Crack-opening load was measured throughout the test from automated compliance measurements and was used to adjust fatigue crack growth data for crack closure. For ?-21S, fatigue crack growth rates were similar at 175 and 25°C at a stress ratio of 0.1, while crack growth rates were lower at 175 versus 25°C at a stress ratio of 0.5 for the same nominal ?K. Concepts associated with crack closure accounted for this as crack growth rates were found to be higher at 175°C than 25°C for both stress ratios when plotted as a function of ?Keff, showing a temperature dependency on crack growth rate. For Ti-62222, fatigue crack growth rates were comparable between 25 and 175°C for R = 0.5, but were different at R = 0.1 where crack closure was observed at 175°C. Fatigue crack growth behavior of these two titanium alloys was comparable for all loading and temperature conditions.

Download or read book Journal of Advanced Materials written by and published by . This book was released on 2002 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue crack Propagation in Several Titanium and Stainless steel Alloys and One Superalloy written by C. M. Hudson and published by . This book was released on 1964 with total page 40 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 Mean Stress and Environmental Effects on Near Threshold Fatigue Crack Propagation on a Ti6246 Alloy at Room Temperature and 500 C written by C. Sarrazin-Baudoux and published by . This book was released on 2000 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cracking behavior of a Ti6246 alloy under cyclic loading superimposed to different levels of mean stress is studied, with special attention to the near-threshold fatigue crack propagation regime, and to possible coupled effects of corrosion and creep. Tests were conducted at room temperature and 500°C in selected environmental conditions (high vacuum, controlled atmospheric leak low pressure, controlled partial pressure of water vapor in pure argon) and at different frequencies. The near-threshold crack propagation at low Kmax (i.e. low R ratio) is shown to be highly sensitive to the environment, and a predominant detrimental influence of water vapor is observed, even under very low partial pressure. Conditions for the occurrence of an abnormal behavior consisting in the disappearance of the threshold for sufficiently high Kmax level, are discussed from tests performed at various constant Kmax levels in ambient air, high vacuum and humidified argon. This effect is observed in air and in vacuum for Kmax higher than 52 MPa?m, and is related to an intrinsic creep damage process which appears more efficient at room temperature than at 500°C and more accentuated in air than in vacuum. The origin of this abnormal near-threshold behavior is discussed in comparison with a similar behavior described in the literature at room temperature on another type of Ti6246 alloy and at 120°C on an IMI834. Additional experiments conducted at 500°C in humidified argon have shown a critical Kmax level reduced to 22 MPa?m. This behavior is suspected to be related to a contribution of stress corrosion cracking induced by water vapor when some conditions favoring a localization of the deformation and the attainment of a critical embrittlement are fulfilled.

Download or read book Elevated Temperature Effects on Fatigue and Fracture written by Robert S. Piascik and published by ASTM International. This book was released on 1997 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Accelerated Near Threshold Fatigue Crack Growth Behavior of an Aluminum Powder Metallurgy Alloy written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-27 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low DK, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = Kmin/Kmax). The near threshold accelerated FCG rates are exacerbated by increased levels of Kmax (Kmax less than 0.4 KIC). Detailed fractographic analysis correlates accelerated FCG with the formation of crack-tip process zone micro-void damage. Experimental results show that the near threshold and Kmax influenced accelerated crack growth is time and temperature dependent. Piascik, Robert S. and Newman, John A. Langley Research Center NASA/TM-2002-211676, L-18180, NAS 1.15:211676, ARL-TR-2728

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975-05 with total page 1154 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 Influence of Crack Closure and Stress Ratio on Near Threshold Fatigue Crack Growth Behavior in Ti 1100 written by T. Nicholas and published by . This book was released on 1994 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the present study, the fatigue crack growth behavior of a near-?, ?-processed titanium alloy, Ti-1100, was investigated with the objective of assessing the influence of crack closure and stress ratio on fatigue threshold. Measurement of the crack-opening load in single-edge tension [SE(T)] specimens was made by near-tip strain gage and DCPD methods. Fatigue threshold stress intensity ranges, ?Kth, determined under constant stress ratio and constant maximum stress intensity, variable stress ratio conditions indicate almost identical values for R above 0.5. It is postulated that while crack closure in the wake of the crack tip is responsible for the no-growth condition in the former case, lack of sufficient damage accumulation at the crack tip as a consequence of the formation of an insignificant reversed plastic zone and large planar slip band formations surrounding the crack tip appears to be responsible for no growth in the latter case. The use of an effective stress intensity based on closure data consolidates most of the threshold data, indicating the independence of the fatigue crack growth data to mean stress or R.