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rate of diffusion

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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.c9001834
EISBN: 978-1-62708-241-9
... observed on the inner wall showed obvious vapor oxidation corrosion characteristics. Corrosion originated in the grain boundary, and selective oxidation occurred due to ion diffusion in the substrate. The layered oxide scale on the inner wall is related to the different diffusion rates for different...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001816
EISBN: 978-1-62708-241-9
... A material is considered to have superplastic behavior when it shows extremely high and uniform elongations (from 100 to 1000%) under tension stress: a lack of localized necking or a series of diffuse necks along the test zone resulting from a combination of the creep tension stress and the strain rate...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001133
EISBN: 978-1-62708-214-3
... (2600 °F) for a 0.30% C alloy to up to 1495 °C (2720 °F) for pure cobalt. Because the rate of diffusion and consequently the rate of diffusion bonding are functions of homologous temperature ( T/T melting ), the lower-carbon surface layer can be expected to inhibit diffusion and significantly reduce...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001304
EISBN: 978-1-62708-215-0
...Abstract Abstract An exhaust diffuser assembly failed prematurely in service. The failure occurred near the intake end of the assembly and involved fracture in the diffuser cone (Corten), diffuser in take flange (type 310 stainless steel), diffuser exit flange (type 405 stainless steel...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c9001738
EISBN: 978-1-62708-220-4
... diffusion (Coble creep) is the acting deformation mechanism for Incoloy 800H at 800°C and low stresses (typically σ < 30 MPa). The creep rate of the aged material is between 5 · 10 −11 and 7 · 10 −10 1/s. The residual life, in this case defined as the time to reach 7% elongation, is between 20,000...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.mech.c0048634
EISBN: 978-1-62708-225-9
... diffusion of mobile hydrogen outward from the surface of the pin. After the cadmium layer was removed, the mobile hydrogen contained on the surface of the steel and in the electroplated deposit was released, and the embrittlement problem was alleviated. To prevent reoccurrence, the bright cadmium layer...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003555
EISBN: 978-1-62708-180-1
... to cracking. Fig. 6 Formation of chromium sulfides (gray areas, such as marked by arrow) along the surface, caused by diffusion of sulfur species along the grain boundaries of IN-690 liner. As expected, sulfide concentration decreases with depth, due to diffusion limitations. Precipitates formed...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.petrol.c0048830
EISBN: 978-1-62708-228-0
... the diffusion of hydrogen into the metal in the cracked region. The resultant embrittlement and associated fissuring was established to have caused the failure. The hydrogen was diffused out by wrapping the vessel in asbestos and heating followed by cooling as prescribed by ASME code. Hydrogen reformers...
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
... that incorporates a diffusion coefficient, t is the time of high-temperature exposure, and n is a rate-limiting step-specific exponent. Note that in some alloy systems, notably nickel-base superalloys in which strengthening is achieved by optimal use of Ni 3 -Al precipitates, surface oxidation manifests...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001616
EISBN: 978-1-62708-229-7
... was only 108 °C. This high heat transfer rate in Stage 3 would have resulted in condensation of some flue gas constituents on the ID of the tube. These condensed phases later diffused into the base metal due to extended non-operation of the plant. The heat transfer was more in the areas where the airflow...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006787
EISBN: 978-1-62708-295-2
... rate increases with increasing volume fraction of liquid. Courtesy of Z. Tang and B. Gleeson, University of Pittsburgh Fig. 22 Schematic diagram of shipboard engine corrosion rates of type I and type II hot corrosion versus temperature in a marine environment compared with the Arrhenius...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.bldgs.c9001702
EISBN: 978-1-62708-219-8
... that of the original concrete. The patch concrete was more permeable to mass transfer of fluids than the original concrete. Chloride diffusion rates were higher in the patch concrete than the original concrete. There were some differences between the aggregate in the patch concrete compared to the original concrete...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.marine.c9001003
EISBN: 978-1-62708-227-3
... to the rates experienced in the present failures. The diffusivity of the hydrogen is certainly adequate to move it throughout the steel; but at ambient temperature the carbon cannot move to the inclusion, high-angle grain boundaries, or whatever special site is required to permit reaction with the hydrogen...
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
... be particularly damaging, because many of the baths produce heavy concentrations of atomic hydrogen at the interface of the base material and plated layer. While the hydrogen atoms can diffuse readily into the iron matrix of the steel, the zinc or cadmium plating acts as a barrier to any hydrogen atoms that may...
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
... can be as high as 150 °C and is sometimes quoted as being up to 190 °C [ 7 ]. Temperature increases caused by spallation of top coat can increase diffusion rate. In the welded region ( Fig. 4c ), the composition of cobalt and nickel at the substrate are more analogous to bond coat. Compared...
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
... formation has been observed at levels as low as 40 or 50 ppm of hydrogen. Figure 10 is an example of hydrided titanium. Fig. 10 Severely hydrided unalloyed titanium At temperatures near the boiling point of water, the diffusion rate of hydrogen into the metal is relatively slow...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001447
EISBN: 978-1-62708-235-8
... monoxide. 8 The diffusion rate of hydrogen is more than 105 times greater than that of carbon monoxide at the same temperatures. 8 Fig. 7 Influence of hydrogen and temperature on incubation for heating periods of 1 1 2 hours. In some instances, the hydrogen driven off from...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001827
EISBN: 978-1-62708-241-9
... corrosion. Therefore, surface protection is required to minimize this effect. To protect and delay the destructive hot corrosion action, special corrosion protective coatings of two types, aluminide or chromium (diffusion) coatings and overlay coatings, are applied. Also to reduce the exposure...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001396
EISBN: 978-1-62708-229-7
.... Potassium salts, instead of sodium, have been recommended as being less likely to suffer from this effect, but experience indicates that, overall, they have no practical advantage. Since the presence of magnetite scabs appears to result from a diffusion process and the rate-controlling factors...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003538
EISBN: 978-1-62708-180-1
... that can cause specimen-scale shear banding is the combination of minimum strain hardening and negative strain rate hardening. A second case in which the central fibrous zone is (apparently) absent has been reported in an HY-100 steel. Both cases are discussed in this article. When edge- or center...