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time-temperature dependence

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Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001829
EISBN: 978-1-62708-241-9
...Abstract Abstract An investigation was conducted to better understand the time-dependent degradation of thermal barrier coated superalloy components in gas turbines. First-stage vanes are normally subjected to the highest gas velocities and temperatures during operation, and were thus the focus...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0001812
EISBN: 978-1-62708-180-1
...-and-nut bearing surfaces, and the use of locking devices, the assumption is that the initial clamping force will be sustained during the life of the fastened joint. This assumption cannot be made in elevated-temperature design. At elevated temperature, the induced bolt load will decrease with time...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006780
EISBN: 978-1-62708-295-2
.... For example, a creep failure of a cobalt-base alloy turbine vane is shown in Fig. 1 . The bowing is the result of a reduction in creep strength at the higher temperatures from overheating. Failures from creep deformation depend on material, time-temperature exposure, loading conditions, component...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003545
EISBN: 978-1-62708-180-1
... extension. Depending on the alloy, temperature, and strain rate, stress-rupture fracture may be macroscopically either ductile or brittle. A macroscale brittle fracture usually is intergranular and occurs with little elongation or necking. In general, lower creep rates, longer rupture times, or higher...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003517
EISBN: 978-1-62708-180-1
... are often conducted on time-dependent failure mechanisms. The principal types of elevated-temperature failures are stress rupture, creep, low- or high-cycle fatigue, thermal fatigue, and coating degradation in gas turbines. For high-temperature tubing and piping components, embrittlement phenomena can occur...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006781
EISBN: 978-1-62708-295-2
..., and elevated temperatures may increase the rate of dislocation movement. This last example is not to be confused with the time-dependent damage mechanism of creep. Elevated-temperature-assisted inelastic deformation may occur by discrete obstacle resistance to dislocation motion, lattice resistance...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003569
EISBN: 978-1-62708-180-1
... pump impeller by cavitation and solid particle erosion. Courtesy of CETIM Fig. 13 Incubation time of different metals and alloys (frequency = 21.1 kHz; distance between specimen and vibration horn = 0.9 mm; vibration amplitude = 35 μm; temperature = 20 °C; liquid: water). Source: Ref 30...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003543
EISBN: 978-1-62708-180-1
... stress: small fatigue zone • Mild overheating and/or mild overstressing at elevated temperature• Unstable microstructures and small grain size increase creep rates• Ruptures occur after long exposure times• Verify proper alloy (a) Failure at the time of load application without prior weakening...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003573
EISBN: 978-1-62708-180-1
.... Creep, or time-dependent strain, is a relatively long-term phenomenon and can be distinguished from overload distortion by relating the length of time at temperature to the amount of distortion, as discussed in the article “Creep and Stress Rupture Failures” in this Volume. The specific mechanisms...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006797
EISBN: 978-1-62708-295-2
... and stress relaxation are time-dependent phenomena. Exposure to elevated temperature for an extended length of time, typically hours to thousands of hours, is necessary for creep or stress relaxation to occur, but extensive deformation by ratcheting can occur in short periods of time—sometimes only minutes...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003510
EISBN: 978-1-62708-180-1
.... The formation of these products and the proportions of each are dependent on the time and temperature cooling history of the particular alloy and the elemental composition of that alloy. The transformation products formed are typically illustrated with the use of transformation diagrams, which show...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003546
EISBN: 978-1-62708-180-1
.... In addition, high-temperature damage accumulation mechanisms such as oxidation and creep depend not only on temperature and stress, but also on time. Thus it is important to precisely duplicate cycle times when carrying out a simulation. For these reasons, in many cases it appears as if the life computed from...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006778
EISBN: 978-1-62708-295-2
... and environmental factors, such as grain-boundary embrittlement and decohesive separation along the grain boundaries at elevated (creep-regime) temperatures. For service temperatures below the creep regime (i.e., approximately 0.4 to 0.5 times the melting temperature of the alloy) and with appropriate materials...
Book Chapter

Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003541
EISBN: 978-1-62708-180-1
... 12 ). The deformation and fracture behavior is generally a complex phenomenon that varies with material composition, microstructure, stress environment, time, and temperature ( Ref 4 ). Such behavior for polymers, like metals, depends on external loading conditions, component geometry...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006784
EISBN: 978-1-62708-295-2
... temper embrittlement. Characteristics that should be considered in evaluating the possibility of hydrogen embrittlement include: The severity of hydrogen attack depends on temperature, hydrogen partial pressure, stress level, exposure time, and steel composition. Additions of chromium...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003552
EISBN: 978-1-62708-180-1
... of bath composition and temperature is also very important. Proper maintenance of acid concentration, temperature, time in the bath, uniformity of any special or proprietary bath additives, as well as proper racking or tumbling to allow draining and rinsing after the cleaning help to minimize...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.9781627082952
EISBN: 978-1-62708-295-2
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006779
EISBN: 978-1-62708-295-2
...Abstract Abstract Fatigue failures may occur in components subjected to fluctuating (time-dependent) loading as a result of progressive localized permanent damage described by the stages of crack initiation, cyclic crack propagation, and subsequent final fracture after a given number of load...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001279
EISBN: 978-1-62708-215-0
.... The arrows indicate the damaged areas. Tube 3 is to the left and Tube 4 is to the right. Fig. 2 Photomacrographs of the damaged areas of (a) Tube 3 and (b) Tube 4. Metallography Mechanical Properties Stress Analysis Creep is a long-term failure mechanism depending on time...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003524
EISBN: 978-1-62708-180-1
... fracture, it is important to know if, at the time of the accident or failure, the prevailing temperature was low, and/or if some measure of shock loading was involved. When dealing with failures of crankshafts or other shafts, it is generally desirable to ascertain the conditions of the bearings...