HETEROGENEOUS NUCLEATION OF SOLIDIFICATION OF SI IN AL-SI AND AL-SI-P ALLOYS
HETEROGENEOUS NUCLEATION OF SOLIDIFICATION OF SI IN AL-SI AND AL-SI-P ALLOYS
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DOI：
10.1016/0956-7151(94)00480-6
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发表时间：
1995-08-01
期刊：
影响因子：
--
通讯作者：
CANTOR, B
中科院分区：
文献类型：
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作者：
HO, CR;CANTOR, B
本文用差示扫描量热法、透射、扫描透射和高分辨电子显微镜研究了快淬Al-Si和Al-Si-P合金凝固的异质形核。热处理后的合金组织均由Al基体、沿着Al晶界分布的Al-Si共晶和镶嵌在Al基体中的Si组成。Si显微结构取决于P：在含有2 ppm P的Al-Si和含有35 ppm P的Al-Si-P中，粗糙的有小面的Si颗粒被AlP颗粒成核，而细Si颗粒的共晶液滴在Al中的深过冷下被周围的Al基体成核。Si含有0.25ppm P。Si成核起始温度保持大致恒定，而峰值和终止温度都随着冷却速率的增加而降低，与经典成核理论一致。动力学分析，使用球冠模型给出的接触角为10度，43度和10度的硅形核在低和高纯度Al-Si和Al-Si-P分别。
Heterogeneous nucleation of solidification in melt spun Al-Si and Al-Si-P has been studied using differential scanning calorimetry, and transmission, scanning transmission and high resolution electron microscopies. The microstructures of the heat treated melt spun alloys all consist of an Al matrix, Al-Si eutectic distributed along the Al grain boundaries, and Si embedded in the Al matrix. The Si microstructure depends on the level of P: coarse faceted Si particles are nucleated by AlP particles in Al-Si containing 2 ppm P and Al-Si-P containing 35 ppm P whereas eutectic droplets of fine Si particles are nucleated by the surrounding Al matrix at a high undercooling in Al-Si containing 0.25 ppm P. The Si nucleation onset temperature remains approximately constant while the peak and end temperatures both decrease with increasing cooling rate, in agreement with classical nucleation theory. Kinetic analysis, using the spherical cap model gives contact angles of 10 degrees, 43 degrees and 10 degrees for Si nucleation in low and high purity Al-Si and Al-Si-P respectively.