Diffusion-coefficient measurements in liquid metallic alloys

Lee, J. H.; Liu, Shan; Miyahara, Hirofumi; Trivedi, R.

doi:10.1007/s11663-004-0085-6

Cited by 49 publications

(31 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…specimen diameter) [124,251]. The stability parameter r was found to be the same for solidification with or without convection only when the effective diffusion coefficient was used to compute r in the case with convection.…”

Section: Dendrite Tip Growthmentioning

confidence: 95%

Solidification microstructures and solid-state parallels: Recent developments, future directions

et al. 2009

Self Cite

View full text Add to dashboard Cite

Rapid advances in atomistic and phase-field modeling techniques as well as new experiments have led to major progress in solidification science during the first years of this century. Here we review the most important findings in this technologically important area that impact our quantitative understanding of: (i) key anisotropic properties of the solid-liquid interface that govern solidification pattern evolution, including the solid-liquid interface free energy and the kinetic coefficient; (ii) dendritic solidification at small and large growth rates, with particular emphasis on orientation selection; (iii) regular and irregular eutectic and peritectic microstructures; (iv) effects of convection on microstructure formation; (v) solidification at a high volume fraction of solid and the related formation of pores and hot cracks; and (vi) solid-state transformations as far as they relate to solidification models and techniques. In light of this progress, critical issues that point to directions for future research in both solidification and solid-state transformations are identified.

show abstract

Section: Dendrite Tip Growthmentioning

confidence: 95%

Solidification microstructures and solid-state parallels: Recent developments, future directions

et al. 2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…The convex shape of the solid phase, with the presence of quenched liquid near the surface of the crucible, indicates that solutal convection of zinc is from the center to the periphery of the specimen, i.e., of a solidus isotherm that is also convex (i.e., the radial component of the thermal gradient, G r , is positive). In order to limit the influence of convection on the measurement of diffusion coefficients [29,37], the diameter of the specimens was reduced from 4 mm ( Fig. 1) to 1.2 mm.…”

Section: Effect Of Convectionmentioning

confidence: 99%

“…Under such conditions, it is more difficult to reach steady state but the diffusion coefficient D [ can still be deduced from the solute profile ahead of the planar solid-liquid interface in the transient regime [29].…”

Section: Introductionmentioning

confidence: 99%

Influence of icosahedral short range order on diffusion in liquids: A study on Al-Zn-Cr alloys

2016

View full text Add to dashboard Cite

a b s t r a c tIt has been shown recently that minute additions of Cr in Al-Zn alloys refine the solidified grain structure and induce multiply-twinned grains which can only be explained if the icosahedral symmetry is considered (Kurtuldu et al., 2013). It has been suggested that Cr addition to Al-Zn alloys promotes the formation of icosahedral short-range order (ISRO) in the liquid, leading to the formation of icosahedral quasicrystals (iQC) acting then as a template for the nucleation of the fcc Al-phase. If ISRO exists in liquid Al-Zn-Cr alloys, this should influence diffusion of solute elements in the liquid. The present study focuses on the effect of Cr addition on Zn diffusion in liquid Al-Zn-Cr alloys. The solute diffusion coefficients of Zn and Cr in the liquid were deduced from the solute profiles in the quenched liquid ahead of a planar solidliquid interface. By comparison with the same measurement in Al-Zn alloys, it is shown that Cr indeed slows down the diffusion (and mobility) of Zn atoms, an effect which reinforces the hypothesis of ISRO in Al-Zn liquid induced by Cr.

show abstract

“…An approximate interpretation of these results has been obtained by considering the local microstructure and the local composition by Trivedi et al [21] for a single phase and for a eutectic growth in the Al-Cu system, and by Dobler et al [16] for peritectic growth in the Fe-Ni system. However, the interpretation based on local condition is not accurate since Lee et al [23] have shown that the fluid flow also enhances the mass transport in the liquid so that a larger value of the effective diffusion coefficient needs to be used. This effective diffusion coefficient is not constant but varies along the radial direction.…”

Section: Introductionmentioning

confidence: 99%

“…This effective diffusion coefficient is not constant but varies along the radial direction. [23] Consequently, a quantitative interpretation of these results is possible only if the variations in composition as well as in the effective diffusion coefficient in the radial direction are known precisely.…”

Section: Introductionmentioning

confidence: 99%

Phase selection during directional solidification of peritectic alloys

Lograsso

Fuh

Trivedi

2005

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

Directional solidification studies have been conducted using Pb-Bi peritectic alloys over a wide range of compositions, temperature gradients, and growth velocities to characterize the primary α-to primary β-phase transitions, which have been observed at both very low and very high velocities. The critical conditions for these transitions correspond to the simultaneous growth of the α and β phases at or close to a single isotherm. The low velocity transition occurs under very specific conditions of composition, temperature gradient, and growth velocity. Since the transition conditions are composition dependent, they change continuously under terrestrial conditions where rejected solute is convectively mixed into the liquid. Detailed experimental studies have been carried out to examine the phase selection in the immediate vicinity of the critical velocity for the α to β transition, and the effect of convection on this transition is examined experimentally in the Pb-Bi system. The dynamic condition, at which both phases are present at the same isotherm, was shown to depend not only on velocities, temperature gradients, and bulk (nominal) alloy compositions, but also on the volume fractions of solid. A quantitative expression for the α-to β-phase transition condition was obtained by using the boundary layer model of fluid flow, which showed good agreement with the experimental results. It is shown that the transition occurs at the volume fraction where the bulk composition reaches the critical composition value predicted by the diffusive model. The modification in the microstructure map for the trailing planar or nonplanar β phase is discussed. Disciplines Metallurgy CommentsCopyright 2005 ASM International. This paper was published in Metallurgical and Materials Transactions A, Vol. 36, Issue 5, pp. 1287-1300, and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited. Directional solidification studies have been conducted using Pb-Bi peritectic alloys over a wide range of compositions, temperature gradients, and growth velocities to characterize the primary ␣-to primary ␤-phase transitions, which have been observed at both very low and very high velocities. The critical conditions for these transitions correspond to the simultaneous growth of the ␣ and ␤ phases at or close to a single isotherm. The low velocity transition occurs under very specific conditions of composition, temperature gradient, and growth velocity. Since the transition conditions are composition dependent, they change continuously under terrestrial conditions where rejected solute is convectively mixed into the liquid. Detailed experimental studies have been carried out to examine the phase selection in ...

show abstract

Diffusion-coefficient measurements in liquid metallic alloys

Cited by 49 publications

References 33 publications

Solidification microstructures and solid-state parallels: Recent developments, future directions

Solidification microstructures and solid-state parallels: Recent developments, future directions

Influence of icosahedral short range order on diffusion in liquids: A study on Al-Zn-Cr alloys

Phase selection during directional solidification of peritectic alloys

Contact Info

Product

Resources

About