| Solidification characteristics of Pb-Sb hypereutectic alloy within ultrasonic field |
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| 作者姓名： | ZHAI Wei HONG ZhenYu XIE WenJun WEI BingBo |
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| 作者单位： | Department of Applied Physics, Northwestern Polytechnical University, Xi＇an 710072, China |
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| 基金项目： | Supported by-the National Natural Science Foundation of China （Grant Nos. 50121101, 50395105 and 50301012） and the Graduate Starting Seed Fund of Northwestern Polytechnical University |
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| 摘 要： | The solidification of Pb-16%Sb hypereutectic alloy is investigated within ultrasonic field with a fre-quency of 15 kHz. It is found that the ultrasonic field promotes crystal nucleation and terminates the further bulk undercooling of the alloy melt. Theoretical analysis shows that the cavitation effect and the forced bulk vibration are the main factors that reduce the undercooling level. With the increase of ul-trasound intensity, the primary (Sb) phase experiences a growth mode transition from faceted to non-faceted branched growth, and the macrosegregation of primary (Sb) phase is gradually sup-pressed. In addition, the microstructures of Pb-Sb eutectic exhibit a conspicuous coarsening with in-creasing ultrasound intensity, and a structural transition of “lamellar eutectic—anomalous eutectic” occurs when ultrasound intensity rises up to 1.6 W/cm2. The ultrasonic field also changes the solute distribution adjacent to the solidification front, which lowers the Pb contents in primary (Sb) phase.
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| 关 键 词： | 铅-锑过共晶合金 超声场 凝固特性 空化效应 强制振动 |
| 收稿时间： | 21 July 2006 |
| 修稿时间： | 2006-07-212006-09-06 |
Solidification characteristics of Pb-Sb hypereutectic alloy within ultrasonic field |
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| ZHAI Wei HONG ZhenYu XIE WenJun WEI BingBo.Solidification characteristics of Pb-Sb hypereutectic alloy within ultrasonic field[J].Chinese Science Bulletin,2007,52(6):844-848. |
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| Authors: | Zhai Wei Hong ZhenYu Xie WenJun Wei BingBo |
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| Institution: | (1) Department of Applied Physics, Northwestern Polytechnical University, Xi’an, 710072, China |
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| Abstract: | The solidification of Pb-16%Sb hypereutectic alloy is investigated within ultrasonic field with a frequency of 15 kHz. It
is found that the ultrasonic field promotes crystal nucleation and terminates the further bulk undercooling of the alloy melt.
Theoretical analysis shows that the cavitation effect and the forced bulk vibration are the main factors that reduce the undercooling
level. With the increase of ultrasound intensity, the primary (Sb) phase experiences a growth mode transition from faceted
to non-faceted branched growth, and the macrosegregation of primary (Sb) phase is gradually suppressed. In addition, the microstructures
of Pb-Sb eutectic exhibit a conspicuous coarsening with increasing ultrasound intensity, and a structural transition of “lamellar
eutectic—anomalous eutectic” occurs when ultrasound intensity rises up to 1.6 W/cm2. The ultrasonic field also changes the solute distribution adjacent to the solidification front, which lowers the Pb contents
in primary (Sb) phase.
Supported by the National Natural Science Foundation of China (Grant Nos. 50121101, 50395105 and 50301012) and the Graduate
Starting Seed Fund of Northwestern Polytechnical University |
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| Keywords: | cavitation effect acoustic streaming forced vibration eutectic growth |
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