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diffusion coefficient

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Series: ASM Technical Books
Publisher: ASM International
Published: 31 December 2020
DOI: 10.31399/asm.tb.phtbp.t59310029
EISBN: 978-1-62708-326-3
... on iron phase transformation, hysteresis in heating and cooling, ferrite and austenite as two crystal structures of solid iron, and the diffusion coefficient of carbon. austenite bainite carbon cementite diffusion coefficient ferrite heat treatment iron martensite microstructure...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2007
DOI: 10.31399/asm.tb.smnm.t52140063
EISBN: 978-1-62708-264-8
... the bar to the carbon-depleted surface The rate at which diffusion occurs is characterized by a parameter, D , called the diffusion coefficient. To a good approximation, one may calculate how long it will take a carbon atom to diffuse a distance, d , by dividing the distance squared by six...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2012
DOI: 10.31399/asm.tb.pdub.t53420239
EISBN: 978-1-62708-310-2
... cooled to room temperature. This process generates less thermal stress in the samples, making lattice parameter measurements more accurate. Homogenization is achieved through diffusion, thus the annealing time and temperature are two important factors. Because the diffusion coefficient increases...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2002
DOI: 10.31399/asm.tb.stg2.t61280135
EISBN: 978-1-62708-267-9
... such changes are required. It describes several types of treatments, including stress relieving, in-process annealing, full annealing, solution annealing, coating diffusion, and precipitation hardening. It discusses the temperatures, holding times, and heating and cooling rates necessary to achieve the...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2002
DOI: 10.31399/asm.tb.stg2.t61280287
EISBN: 978-1-62708-267-9
.... In general, protective oxidation involves the diffusional transport of one or more of the reactants through the oxide layer, and it is plainly desirable that an oxide with a slow transport rate should be formed. In practice, therefore, it is common to aim for a continuous CrO 3 layer, and the slow...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2007
DOI: 10.31399/asm.tb.smnm.t52140107
EISBN: 978-1-62708-264-8
... homogenization. The homogenization time is dependent on two variables: the diffusion coefficient of the atoms, D , and the distance the atoms must diffuse, d . Both variables have strong effects. Increasing temperature increases D rapidly and decreases the homogenization times. Increasing d , the distance...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2016
DOI: 10.31399/asm.tb.ascaam.9781627082969
EISBN: 978-1-62708-296-9
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2010
DOI: 10.31399/asm.tb.scm.t52870401
EISBN: 978-1-62708-314-0
... available, and considerable work has been performed in the area of moisture absorption. The most interesting feature of the solutions to Eq 15.3 relates to the magnitude of the coefficient D x , which is a measure of the speed of moisture diffusion. In typical epoxy matrix systems, D x is on the...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.tb.ssde.t52310057
EISBN: 978-1-62708-286-0
... serve as the “electron lead” in the electrochemical cell in Fig. 4b . The free energy of Reaction 4 determines the concentration of mobile defects and thus the diffusion coefficient and electrochemical mobility ( B e ) of the cation according to: (Eq 5) D C r 3 + = [ V...
Series: ASM Technical Books
Publisher: ASM International
Published: 31 December 2020
DOI: 10.31399/asm.tb.phtbp.9781627083263
EISBN: 978-1-62708-326-3
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2007
DOI: 10.31399/asm.tb.smnm.t52140165
EISBN: 978-1-62708-264-8
... austenite at 1100 °C (2010 °F). Also, if the carbon diffusion coefficient were high enough and the steel were cooled slow enough, carbon would migrate by diffusion into the core regions of the austenite dendrites sufficiently to produce a homogeneous austenite having %C = 1.8 throughout at 1100 °C (2010 °F...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2001
DOI: 10.31399/asm.tb.aub.t61170234
EISBN: 978-1-62708-297-6
...-range ordering reaction in the matrix that involves cobalt. Molybdenum also plays the necessary supplemental role of minimizing localized grain-boundary precipitation by lowering the diffusion coefficients of a number of elements in solid solution. Precipitation of these grain-boundary phases...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2007
DOI: 10.31399/asm.tb.smnm.t52140083
EISBN: 978-1-62708-264-8
... levels in the carbides that form and lower levels in the ferrite that forms. However, the diffusional rearrangement of the alloying elements is more difficult than it is for carbon because of their tremendously smaller diffusion coefficients, as illustrated in Table 7.1 . Therefore, their presence makes...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110196
EISBN: 978-1-62708-247-1
... resolution of electrical effects on the device is limited by carrier diffusion lengths and carrier lifetimes, thermal conduction, device structure as well as spot size. By using different laser wavelengths and intensities, variations in the amount of photocurrent can be obtained and backside photon probing...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110180
EISBN: 978-1-62708-247-1
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2012
DOI: 10.31399/asm.tb.pdub.t53420429
EISBN: 978-1-62708-310-2
... the time, t , required to diffuse a solute over a given average distance, x . If the coefficient of diffusion in the solid is D , then the relationship between time and distance is approximately: (Eq B.3) x = D t Fig. B.10 Effect of solidification time on secondary dendrite...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2007
DOI: 10.31399/asm.tb.smnm.t52140071
EISBN: 978-1-62708-264-8
... iron atoms of the bcc or fcc lattice sites, they will have very low diffusion coefficients (compare Fig. 7.6 to Fig. 7.5 ). Therefore, as the grain boundary moves, it must drag the solute atoms along with it, and the solute atoms will exert a drag force on the boundary and slow down its migration...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 September 2008
DOI: 10.31399/asm.tb.fahtsc.t51130241
EISBN: 978-1-62708-284-6
... diffusion case, heat treated to the same condition as the heat-treated-only version. Once these values were known, the surface coefficient of strengthening was determined from the equation: (Eq 5) m = σ − 1 w w σ − 1 where σ − 1 w w is the fatigue...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2010
DOI: 10.31399/asm.tb.scm.t52870537
EISBN: 978-1-62708-314-0
... to their base metals, such as higher specific strengths and moduli, higher elevated-temperature resistance, lower coefficients of thermal expansion, and, in some cases, better wear resistance. However, due to their high cost, commercial applications for MMCs are few. There are some limited uses for...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.tb.ssde.t52310069
EISBN: 978-1-62708-286-0
... withstand boiling seawater. If these alloys were to have any relative weaknesses, they would be: Austenitic stainless steels are less resistant to cyclic oxidation than are ferritic grades because their greater thermal expansion coefficient tends to cause the protective oxide coating to spall...