Download or read book Mechanisms of Environmentally Influenced Fatigue Crack Growth in Lower Strength Steels written by Subramanian Suresh and published by . This book was released on 1981 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of Environmentally influenced Near threshold Fatigue crack growth Behavior in High and Lower strength Steels at Conventional Frequencies written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies in a wide variety of steels, of yield strengths ranging from 290 to 1740 MPa, have indicated that environmental influences on corrosion fatigue crack propagation at near-threshold levels (growth rates below approx. 10/sup -6/ mm/cycle), may be markedly different from those at higher growth rates. In this paper, the effect of such environments, specifically dry gaseous hydrogen and moist room air, on near-threshold cyclic crack growth is reviewed and comparisons made between behavior in high and lower strength steels. It is shown that, in lower strength steels (yield strength less than or equal to 700 MPa), near-threshold growth rates in dry hydrogen exceed those in moist air by up to two orders of magnitude at low load ratios only, whereas for steels of strength levels above approx. 700 MPa, the presence of hydrogen results in lower near-threshold growth rates compared to moist air regardless of load ratio. Such behavior is rationalized in terms of the competing effects of hydrogen embrittlement and oxide-induced crack closure mechanisms.

Download or read book Fracture Mechanics fourteenth Symposium Volume 1 Theory and Analysis written by and published by ASTM International. This book was released on with total page 615 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue environmental Crack Propagation in a High Strength Steel written by Thomas Charles Babcock and published by . This book was released on 1969 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Environmentally Influenced Fatigue in High Strength Steels written by AK. Vasudevan and published by . This book was released on 2005 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to identify the environmental influence on fatigue crack growth behavior of three high strength steels: AerMet 100, 300M, and 4340. These steels were subjected to fatigue tests under constant amplitude loading of frequency 10 Hz and stress ratios R = 0.1 and 0.9, in vacuum, air, and 3.5% NaCl solution. The fatigue crack growth was characterized with two driving force parameters, stress intensity range, ?K, and maximum stress intensity, Kmax. Especially, the variation of fatigue crack growth per time, da/dt, with Kmax in 3.5% NaCl solution was evaluated with respect to R, environment, and threshold stress intensity for environmentally assisted cracking (EAC), KIEAC. In addition, the environmental influence on fatigue crack growth was examined with the fractographic features and trajectory path, drawn with the limiting values of ?K and Kmax, ?K* and Kmax*.

Download or read book Environmentally Affected Near Threshold Fatigue Crack Growth in Steels written by S. Suresh and published by . This book was released on 1983 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmentally affected fatigue crack propagation in steels is described for ultralow growth rates (below 10-6 mm/cycle) in terms of the role of crack surface corrosion debris in promoting crack closure. It is shown that the reported effects of gaseous and aqueous environments (air, water, hydrogen, helium, etc.) on near-threshold crack growth in lower strength steels are consistent primarily with an oxide-induced crack closure mechanism. Moist atmospheres, such as humid air and water, are shown to promote the formation of oxide deposits within the crack, which at low load ratios are thickened by fretting-assisted oxidation to maximum thicknesses comparable with cracktip opening displacements. Using ultrasonic techniques, this is shown to increase closure loads and to lower effective alternating stress intensities at the crack tip. Observations that near-threshold growth in dry helium is similar to that in dry hydrogen gas and faster than in air, are shown to be consistent with such concepts since both environments provide a dry atmosphere limiting oxide formation. Extensive data on near-threshold corrosion-fatigue crack growth in ultrahigh-strength (300-M) and lower-strength (21⁄4Cr-1Mo and SA516) steels are examined in the context of this mechanism, and it is found that the threshold for no crack growth (?Ko) is consistent with a maximum excess oxide thickness approximately equal to the pulsating crack-tip displacement (?CTOD). The implications of this and other microscopic mechanisms of closure are discussed in the light of microstructural and environmental influences on near-threshold fatigue.

Download or read book Influence of Viscous Environments on Fatigue Crack Propagation in Lower Strength Steel written by Jye-Len Tzou and published by . This book was released on 1983 with total page 174 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 1987 with total page 1124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Environmental Influence on the Effect of a Single Overload on the Fatigue Crack Growth Behavior on a High Strength Aluminum Alloy written by J. de Fouquet and published by . This book was released on 1990 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The delaying effect of a single overload on the 2024 T351 aluminum alloy covering a wide ?K range has been studied in ambient air, secondary vacuum, and high purity nitrogen (N2). It is shown that for a given environment and an overload ratio, the delay behavior can be rationalized in terms of the peak stress intensity factor corresponding to the overload for the studied test conditions. At low ?K values, the overload effect is confined to a grain. The results obtained show that while the size of the overload affected zone is not affected by the environment, the number of delay cycles at an R ratio of 0.5 in vacuum can be ten times as high as that obtained in the two other environments. At an R ratio of 0.1, at low ?K levels, the delaying effects can be similar in vacuum and in air. The observed effects are explained on the basis of mechanisms governing constant-amplitude crack growth behavior of the studied alloy.

Download or read book Fatigue of Materials written by Subra Suresh and published by Cambridge University Press. This book was released on 1998-10-29 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by a leading researcher in the field, this revised and updated second edition of a highly successful book provides an authoritative, comprehensive and unified treatment of the mechanics and micromechanisms of fatigue in metals, non-metals and composites. The author discusses the principles of cyclic deformation, crack initiation and crack growth by fatigue, covering both microscopic and continuum aspects. The book begins with discussions of cyclic deformation and fatigue crack initiation in monocrystalline and polycrystalline ductile alloys as well as in brittle and semi-/non-crystalline solids. Total life and damage-tolerant approaches are then introduced in metals, non-metals and composites followed by more advanced topics. The book includes an extensive bibliography and a problem set for each chapter, together with worked-out example problems and case studies. This will be an important reference for anyone studying fracture and fatigue in materials science and engineering, mechanical, civil, nuclear and aerospace engineering, and biomechanics.

Download or read book Aerospace Structural Metals Handbook written by and published by . This book was released on 1989 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydrogen Gas Embrittlement written by Hisao Matsunaga and published by Elsevier. This book was released on 2024-01-22 with total page 411 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen Gas Embrittlement: Mechanisms, Mechanics, and Design enables readers to understand complicated hydrogen-material interactions and conduct better material selection and strength design for hydrogen components. The book reviews the fundamental mechanisms of hydrogen embrittlement, the various behaviors of hydrogen in metallic materials such as diffusion, solution, and trapping, and emphasizes the necessary properties for effective strength design of various materials under the influence of hydrogen, including tensile properties, fatigue life, fatigue limit, fatigue crack-growth, and fracture toughness. Sections provide experimental data obtained in hydrogen gas at various pressures and temperatures together with the fractographic observations, including practical interpretation of hydrogen compatibility of materials based on tensile, fatigue and fracture mechanics testing results. Material testing machines and methods, the effects of hydrogen on various BCC steels, austenitic steels, and non-ferrous metals, and practical applications and methods of strength design for hydrogen vessels and components are all included as well. Enables a better understanding of hydrogen-material interactions, allowing for better material selection and strength design Provides insights on the hydrogen-induced degradation of materials strength at the atomic, macroscale and microscale Looks at a number of degradative behaviors in a variety of materials, including BCC steels, austenitic steels and non-ferrous metals Includes verification tests, case studies, applications and experimental data

Download or read book Energy Research Abstracts written by and published by . This book was released on 1985 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1983 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Thresholds written by Jan Bäcklund and published by . This book was released on 1982 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gaseous Hydrogen Embrittlement of Materials in Energy Technologies written by Richard P Gangloff and published by Elsevier. This book was released on 2012-01-16 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many modern energy systems are reliant on the production, transportation, storage, and use of gaseous hydrogen. The safety, durability, performance and economic operation of these systems is challenged by operating-cycle dependent degradation by hydrogen of otherwise high performance materials. This important two-volume work provides a comprehensive and authoritative overview of the latest research into managing hydrogen embrittlement in energy technologies.Volume 1 is divided into three parts, the first of which provides an overview of the hydrogen embrittlement problem in specific technologies including petrochemical refining, automotive hydrogen tanks, nuclear waste disposal and power systems, and H2 storage and distribution facilities. Part two then examines modern methods of characterization and analysis of hydrogen damage and part three focuses on the hydrogen degradation of various alloy classesWith its distinguished editors and international team of expert contributors, Volume 1 of Gaseous hydrogen embrittlement of materials in energy technologies is an invaluable reference tool for engineers, designers, materials scientists, and solid mechanicians working with safety-critical components fabricated from high performance materials required to operate in severe environments based on hydrogen. Impacted technologies include aerospace, petrochemical refining, gas transmission, power generation and transportation. Summarises the wealth of recent research on understanding and dealing with the safety, durability, performance and economic operation of using gaseous hydrogen at high pressure Reviews how hydrogen embrittlement affects particular sectors such as the petrochemicals, automotive and nuclear industries Discusses how hydrogen embrittlement can be characterised and its effects on particular alloy classes

Download or read book Influences of Gaseous Environment on Low Growth rate Fatigue Crack Propagation in Steels Annual Report No 1 January 1980 Report No FPL R 80 1030 written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of gaseous environment is examined on fatigue crack propagation behavior in steels. Specifically, a fully martensitic 300-M ultrahigh strength steel and a fully bainitic 2-1/4Cr-1Mo lower strength steel are investigated in environments of ambient temperature moist air and low pressure dehumidified hydrogen and argon gases over a wide range of growth rates from 10−8 to 10−2 mm/cycle, with particular emphasis given to behavior near the crack propagation threshold .delta.K0. It is found that two distinct growth rate regimes exist where hydrogen can markedly accelerate crack propagation rates compared to air, (1) at near-threshold levels below (5 x 10−6 mm/cycle) and (2) at higher growth rates, typically around 10−5 mm/cycle above a critical maximum stress intensity K/sub max//sup T/. Hydrogen-assisted crack propagation at higher growth rates is attributed to a hydrogen embrittlement mechanism, with K/sub max//sup T/ nominally equal to K/sub Iscc/ (the sustained load stress corrosion threshold) in high strength steels, and far below K/sub Iscc/ in the strain-rate sensitive lower strength steels. Hydrogen-assisted crack propagation at near-threshold levels is attributed to a new mechanism involving fretting-oxide-induced crack closure generated in moist (or oxygenated) environments. The absence of hydrogen embrittlement mechanisms at near-threshold levels is supported by tests showing that .delta.K0 values in dry gaseous argon are similar to .delta.K0 values in hydrogen. The potential ramifications of these results are examined in detail.