An extended morphological stability model for a planar interface incorporating the effect of nonlinear liquidus and solidus
✍ Scribed by Haifeng Wang; Feng Liu; Wei Yang; Zheng Chen; Gencang Yang; Yaohe Zhou
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 636 KB
- Volume
- 56
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
Incorporating the effect of nonlinear liquidus and solidus, an extended morphological stability model for a planar interface was developed under local non-equilibrium conditions both at the solid/liquid interface and in the bulk liquid. The model was adopted to describe the cellular breakdown of the planar interface upon rapid solidification of Si-Sn alloys, and a quantitative agreement was obtained between the model predictions and the experimental results. It has been found that, independent of the effect of non-equilibrium liquid diffusion, two critical interface velocities V min and V max always occur, because of the retrograde characters of the Si-Sn phase diagram. If V min 6 V 6 V max , the so-called neutral stability curve can be evaluated in terms of the planar interface response function and the marginal stability criterion. Whereas if V > V max or V < V min , the calculation of the maximum solid solubility C max S ðV Þ from the planar interface response function is performed. In comparison with the model assuming linear liquidus and solidus, which fails to predict the retrograde characters of the Si-Sn phase diagram both at low (k ? k e ) and at high (k ? 1) interface velocities, the effect of nonlinear liquidus and solidus on the cellular breakdown of the planar interface is highlighted.