Experimental observations of dendritic growth

Primary dendrite spacing of directionally solidified lead rich Pb--Sn binary alloys

“…is defined as the steady state growth velocity, G the ternperature gradient in the liquid, K the thermal conductivity of the liquid, and ~H the enthalpy of fusion. Equation 1 was shown to agree quite well with the available data for directional solidification (3,20,24) as logarithmic isoconcentrate plots of d vs. v~1 yielded slopes, S, well-within a factor of two of 8D. The effect of solute other than through D was empirically correlated through a form of the well-known (41) solidification parameter C (1-k)/k.…”

Prediction of dendrite arm spacings in unsteady-and steady-state heat flow of unidirectionally solidified binary alloys

“…Kotler et al [30] as well as those by Spittle and Lloyd [31] were also carried out with bottom to top solidification with analogous fluid flow conditions. Burden and co-workers.…”

Macrosegregation in Steel Ingots: The Applicability of Modelling and Characterisation Techniques

“…Although it is true to say that G and R can have different effects on arm spacings when varied independently, [187][188][189][190][191][192] in ingots G and R are coupled by heat flow, and as such they can be combined into a single variable with a single exponent. Expressions which have been developed for dendrite arm spacings in steels have often taken this form, 8,187,[193][194][195][196] see the selection presented in Table 1.…”

“…Secondary-arm spacings, unlike primary spacings, are known to change moving through the mushy zone due to coarsening (GibbsThomson effect), with kinetics that are likely to vary with 7,[187][188][189][193][194][195][197][198][199][200][201][202][203] Accounting for this coarsening is very important in both microsegregation and permeability models, which can be implemented at any location within the mushy zone. Theoretical secondary-arm relations which account for coarsening have been developed, 7,200,201) but they are often more complicated and require many more input parameters (hence, they can deliver very different results to the expressions in Table 1).…”