Correlations for diffusion constants

Brown, Anna M.; Ashby, Michael F.

doi:10.1016/0001-6160(80)90092-9

Cited by 480 publications

(143 citation statements)

References 8 publications

Supporting

Mentioning

121

Contrasting

Unclassified

Order By: Relevance

“…where R is the gas constant and G is given as 10 to 35 by Brown and Ashby [41] and averages 17 for Mehrer [42] for self diffusion in elemental solids. Any movement of species is to be avoided even though the annealing of craters just above the transition temperature appear to be beneficial from a topographical point of view.…”

Section: Depth Resolutionmentioning

confidence: 99%

Systematic Temperature Effects in the Argon Cluster Ion Sputter Depth Profiling of Organic Materials Using Secondary Ion Mass Spectrometry

Seah

Havelund

Gilmore

2016

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

Abstract. A study is presented of the effects of sample temperature on the sputter depth profiling of two organic materials, NPB (N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine) and Irganox 1010, using a 5 keV Ar 2000 + cluster ion beam and analysis by secondary ion mass spectrometry. It is shown that at low temperatures, the yields increase slowly with temperature in accordance with the Universal Sputtering Yield equation where the energy term is now modified by Trouton's rule. This occurs up to a transition temperature, T T , which is, in turn, approximately 0.8T M , where T M is the sample melting temperature in Kelvin. For NPB and Irganox 1010, these transition temperatures are close to 15°C and 0°C, respectively. Above this temperature, the rate of increase of the sputtering yield rises by an order of magnitude. During sputtering, the depth resolution also changes with temperature with a very small change occurring below T T . At higher temperatures, the depth resolution improves but then rapidly degrades, possibly as a result first of local crater surface diffusion and then of bulk inter-diffusion. The secondary ion spectra also change with temperature with the intensities of the molecular entities increasing least. This agrees with a model in which the molecular entities arise near the crater rim. It is recommended that for consistent results, measurements for organic materials are always made at temperatures significantly below T T or 0.8 T M , and this is generally below room temperature.

show abstract

Section: Depth Resolutionmentioning

confidence: 99%

Systematic Temperature Effects in the Argon Cluster Ion Sputter Depth Profiling of Organic Materials Using Secondary Ion Mass Spectrometry

Seah

Havelund

Gilmore

2016

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

“…HEA diffusion is actually faster than in simpler alloys (N = 2-4) when plotting against 1/T, but the opposite trend is observed when comparing against T m /T. 2,25,30 Comparisons using T m /T have a solid physical basis with good support 31 and are preferred, thus, apparently favoring the sluggish diffusion hypothesis. Support for the hypothesis is only found, however, when HEA diffusion is compared against a small number of elements and simpler alloys.…”

Section: Sluggish Diffusion Hypothesismentioning

confidence: 91%

High-Entropy Alloys: A Current Evaluation of Founding Ideas and Core Effects and Exploring “Nonlinear Alloys”

Miracle

2017

JOM

121

View full text Add to dashboard Cite

“…[51] At 673 K (400°C), D l = 1.2 9 10 À3 exp(-143,000/8.314/673) m 2 s À1 and D gb = 1 9 10 À2 exp(-92,000/8.314/673) m 2 s À1 , [52][53][54] giving D gb /D l % 7.5 9 10 4 . Because the grain boundary diffusion coefficient is inversely proportional to the average grain size, the grain boundary diffusion (fD gb ) becomes dominating over lattice diffusion ((1 -f)D l ) when the grain size changes from 100 lm (f = 1 9 10 À5 ) to 10 lm (f = 1 9 10 À4 ); q is taken as 2 in the estimates of f. It is then clear that the average grain size of between~75 lm and~12 lm for the MCTRC strip should have allowed grain boundary diffusion to control homogenization and accelerated kinetics to occur.…”

Section: B Accelerated Homogenizationmentioning

confidence: 99%

“…It can be observed that there is a good straight line fit between 1/T and the logarithmic scale of time; the activation energy of the recrystallization, determined from the slope of the straight line, was 141 kJ mol À1 . Although it is difficult to interpret this value because it refers to the transformation as a whole without differentiating nucleation and growth, its closeness to the activation energy for aluminum diffusion in magnesium [52,53] suggests strongly the importance of aluminum diffusion in the process.…”

Section: Static Recrystallization During Homogenizationmentioning

confidence: 99%

The Impact of Melt-Conditioned Twin-Roll Casting on the Downstream Processing of an AZ31 Magnesium Alloy

Bayandorian

Huang

Fan

et al. 2011

Metall Mater Trans A

View full text Add to dashboard Cite

Melt conditioning by intensive shear was used prior to twin-roll casting of AZ31 magnesium alloy strip to promote heterogeneous nucleation and to provide a refined and uniform microstructure without severe macrosegregation. The cast strip was then processed by homogenization, hot rolling, and annealing, and its downstream processing was compared with a similar cast strip produced without melt conditioning. Melt conditioning produced strip with accelerated kinetics of recrystallization during homogenization and improved performance in hot rolling and improved tensile properties. An average tensile elongation of~28 pct was achieved, which is substantially higher than the~9 pct obtained for the strip produced without melt conditioning which is consistent with reported values (~6 pct to 16 pct). The as-cast, homogenized, and hot-rolled microstructures of the strip were characterized. The kinetics of homogenization and hot-rolling process have been discussed in detail.

show abstract

Correlations for diffusion constants

Cited by 480 publications

References 8 publications

Systematic Temperature Effects in the Argon Cluster Ion Sputter Depth Profiling of Organic Materials Using Secondary Ion Mass Spectrometry

Systematic Temperature Effects in the Argon Cluster Ion Sputter Depth Profiling of Organic Materials Using Secondary Ion Mass Spectrometry

High-Entropy Alloys: A Current Evaluation of Founding Ideas and Core Effects and Exploring “Nonlinear Alloys”

The Impact of Melt-Conditioned Twin-Roll Casting on the Downstream Processing of an AZ31 Magnesium Alloy

Contact Info

Product

Resources

About