| Autor: |
Galenko, P.K., Kolbe, M., Herlach, D.M., Rettenmayr, M. |
| Předmět: |
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| Zdroj: |
Metallurgical Research & Technology; Sep2014, Vol. 111 Issue 5, p295-303, 9p |
| Abstrakt: |
The growth velocity during solidification of an undercooled melt of a Co-Cu alloy processed by electromagnetic levitation was measured using a high speed video camera. Applying a model of local non-equilibrium solidification, theoretical predictions of dendrite growth velocity and dendritic growth radii are compared with high-accuracy measurements of the growth kinetics. As the undercooling ΔT reaches a critical value consistent with the dendrite growth velocity being equal to the atomic diffusion speed VD in bulk liquid, ΔT = ΔT(VD), the velocity-undercooling relationship exhibits a break-point. A distinct change in the dendritic growth mechanism exists with the onset of complete solute trapping and chemically partitionless solidification of the core of the main stems of the dendrites occurs. A complete transition to the thermally controlled growth of dendrites occurs at ΔT = ΔT(VD) that leads to essential changes in the microstructure of dendritic patterns The phenomenon of dendritic fragmentation in Co-Cu melts, solidifying at ΔT < ΔT(VD), is discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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