| Autor: |
Sasikumar, Roschen, Rettenmayr, Markus, Savithri, S., Exner, Hans Eckart |
| Zdroj: |
International Journal of Materials Research: Zeitschrift fuer Metallkunde; December 2021, Vol. 92 Issue: 2 p158-162, 5p |
| Abstrakt: |
A model has been developed describing the growth of pores in a dendritic network. It is assumed that the growing pores originate from pores (bubbles) that preexist in the melt and contain soluble and insoluble gases. The growth of an individual pore is tracked in the model as the cellular/dendritic solidification front passes. As long as the pore surface is not in contact with the solid phase, the pore maintains its spherical shape during cooling/solidification. When the pore size reaches the width of the interdendritic/intercellular channel, it assumes the shape of the channel, pushing the remaining liquid out. In a systematic study, the initial conditions for the numerical calculations are varied in order to investigate the influence of different processing parameters on final porosity and length of pores. Interfacial tension and initial pore size are shown to change the simulation results only sligthly. Solidification shrinkage is shown to have no effect on amount and shape of micropores. With decreasing temperature gradient, porosity increases drastically. Pore elongation is mainly a function of temperature gradient and density of pre-existing pores: pronounced temperature gradients and low initial pore density favour the formation of highly elongated pores. |
| Databáze: |
Supplemental Index |
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