کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9796653 | 1514951 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
On secondary dendrite arm coarsening in peritectic solidification
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
دانش مواد (عمومی)
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
A model for isothermal coarsening of secondary dendrite arms in peritectic reaction and transformation (liquid + primary-phase â peritectic-phase) is proposed to evaluate the secondary dendrite arm spacing (λ2) of the primary phase in directional solidification of peritectic alloys. The model defines three stages for thin-arm dissolution (or thick-arm coarsening), i.e. the initial, intermediate and final stages: the initial thin-arm dissolution through the primary phase is sustained solely by the Gibbs-Thomson effect; the intermediate thin-arm dissolution through the peritectic phase is driven by Gibbs-Thomson effect but retarded by the peritectic reaction and transformation; the final dissolution through the primary and peritectic phases is enhanced by the Gibbs-Thomson effect and the phase transformation. The kinetics of peritectic reaction and transformation were found to be crucial to determine the thin-arm dissolution, which were characterized by the reaction constant (f) and the diffusion coefficient of solute in solid peritectic-phase (DS), respectively. The present model shows that λ2Vm is constant for a given Pb-Bi peritectic alloy, where V is growth velocity, and the factor, m, ranges from 1/3 to 1/2, rather than that normally observed (e.g. 1/3) for single-phase solidification. It is also notable that the calculated λ2 for a Zn-7.37 wt.% Cu peritectic alloy was reasonably consistent with our earlier experiments for various growth velocities.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Science and Engineering: A - Volume 390, Issues 1â2, 15 January 2005, Pages 52-62
Journal: Materials Science and Engineering: A - Volume 390, Issues 1â2, 15 January 2005, Pages 52-62
نویسندگان
D. Ma, W. Xu, S.C. Ng, Y. Li,