The analysis of grain boundary diffusion measurements

Claire, A.D. Le

doi:10.1088/0508-3443/14/6/317

Cited by 602 publications

(225 citation statements)

References 11 publications

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“…4) A comparative study of all three treatments was carried out by LeClaire. 5) According to LeClaire,5) Whipple's expression for concentration contour produced through conjoint action of lattice and grain boundary can be adopted for standard boundary conditions used in tracer experiments. Following LeClaire, 5) it is possible to write…”

Section: Resultsmentioning

confidence: 99%

Volume and Grain Boundary Diffusion of Chromium in Ni-Base Ni-Cr-Fe Alloys

et al. 2003

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Volume and grain boundary diffusion of chromium in Ni-16 mass%Cr-7 mass%Fe alloys containing 0.004, 0.015 and 0.07 mass% of carbon have been measured using radioactive tracer 51 Cr over the temperature range of 858-1424 K by serial radio-frequency sputtermicrosectioning technique. While the volume diffusion coefficients are largely unaffected by the presence of carbon, the increase in carbon content markedly reduces the mobility of chromium atoms along the grain boundaries. As a result, the difference between the activation energy for lattice and grain boundary diffusion decreases with increase in carbon content. In fact, for 0.07 at% carbon, the activation energies for volume and the grain boundary diffusion are nearly same. Among all three alloys, the difference between the volume diffusion coefficient, D v , as well as D gb ( = grain boundary width; D gb = grain boundary diffusion coefficient) decreases gradually in a regular manner with the rise of temperature. Grain bounadry energy is reduced by addition of carbon and enhanced by temperature. At higher temperatures, there is no difference between the grain boundary energies of the three alloys.

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Section: Resultsmentioning

confidence: 99%

Volume and Grain Boundary Diffusion of Chromium in Ni-Base Ni-Cr-Fe Alloys

et al. 2003

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“…Therefore, if an equal value of dln C/dX is obtained for different diffusion times, the deeper region can be attributed to the dislocation pipe diffusion. If the tail slope in the deeper region is caused by the grain boundary diffusion, dln C/dX 6/5 is linear and it depends on diffusion time [17,18].…”

Section: Resultsmentioning

confidence: 99%

Volume and dislocation diffusion of iron, chromium and cobalt in CVD ß-SiC

Takano

Nitta

Seto

et al. 2001

Science and Technology of Advanced Materials

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Impurity tracer diffusion of 59 Fe, 51 Cr and 57 Co in CVD b-SiC has been studied in the temperature range between 973 and 1873 K. The temperature dependence of the volume diffusion coef®cients of iron and chromium can be expressed by linear Arrhenius equations. The preexponential factor and the activation energy are estimated to be 8.7 £ 10 215 m 2 s 21 and 111 kJ mol 21 for iron, respectively, and 9.5 £ 10 215 m 2 s 21 and 81 kJ mol 21 for chromium, respectively. The diffusion coef®cients of iron and chromium are much higher than those of the self-diffusion in b-SiC. Furthermore, the activation energies for the diffusion of iron and chromium are about one-tenth of those for carbon and silicon in b-SiC. Therefore, it seems that an interstitial mechanism is predominant for the diffusion of iron and chromium in b-SiC. On the other hand, the diffusion coef®cient of cobalt above 1673 K is higher than that of iron, while at lower temperatures it is much lower than that of iron. The difference in the diffusion coef®cients at 1173 K is more than three orders of magnitude. Thus, the temperature dependence of the diffusion coef®cients of cobalt shows a strongly curved Arrhenius relation. This suggests that cobalt atoms diffuse by an interstitial mechanism at higher temperatures and by a substitutional mechanism at lower temperatures. From the deeper regions of the penetration pro®les of iron, chromium and cobalt the dislocation diffusion coef®cients of them have been estimated. q

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“…By the same reasons as and Sakaguchi et al (1992) we recognized that the tail can be ascribed to the fast diffusion of 180 along dislocations introduced into the sur face region of the crystal by mechanical treat ment. By analyzing the shapes of the tail, we determined diffusion rates of 0 along the dislocations and along the low angle tilt bound aries' according to the method developed by and Le Claire (1963), respectively. The substance of the method is described in Appendix.…”

Section: Measurement Of Concentration Gradientsmentioning

confidence: 99%

“…Le Claire (1963) and the parameter of a is dislocation pipe radius. Low-angle grain boundaries can be described geometrically as planer arrays of individual dislocations.…”

Section: S2amentioning

confidence: 99%

Oxygen self-diffusion along high diffusivity paths in forsterite.

1992

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Diffusion profiles of 180 tracer in single crystals of forsterite following anneals at 1100° and 1200°C have been determined by a depth profiling technique using secondary ion mass spectrometry. The diffu sion penetration profiles showed error function forms -with developed tails. The profiles were analyzed in terms of diffusion in the forsterite lattice together with a contribution from dislocation. The present results of lattice diffusion lie in the range of the extrapolation of lines on Arrhenius plots reported previously for intracrystalline diffusion in forsterite. The dislocation diffusion coefficients are about 104 times faster than the lattice diffusion at the same temperature.Diffusion along the dislocations takes place within a pipe with radius of about 0.1 nm surrounding the dislocation line. Based on the above results, 0 diffusion along high diffusivity paths, such as dislocations and grain boundaries, play an im portant role on the diffusional creep in olivine under laboratory condition.

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The analysis of grain boundary diffusion measurements

Cited by 602 publications

References 11 publications

Volume and Grain Boundary Diffusion of Chromium in Ni-Base Ni-Cr-Fe Alloys

Volume and Grain Boundary Diffusion of Chromium in Ni-Base Ni-Cr-Fe Alloys

Volume and dislocation diffusion of iron, chromium and cobalt in CVD ß-SiC

Oxygen self-diffusion along high diffusivity paths in forsterite.

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