Evolution of nanoscale precipitates in Al microalloyed with Sc and Er
Evolution of nanoscale precipitates in Al microalloyed with Sc and Er
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DOI：
10.1016/j.actamat.2009.04.034
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发表时间：
2009-08-01
期刊：
影响因子：
9.4
通讯作者：
Seidman, David N.
中科院分区：
文献类型：
--
作者：
Karnesky, Richard A.;Dunand, David C.;Seidman, David N.
研究了过饱和Al-0.06 Sc-0.02 Er（at.%）合金时效过程中α-Al中纳米级共格Al-3（Sc 1-xErx）沉淀的粗化动力学。使用透射电子显微镜和局部电极原子探针断层扫描研究了300摄氏度的合金。铒和钪分别在沉淀物的核和壳处偏析。Er和Sc的基质过饱和度以及平均沉淀物半径和数量密度与粗化模型近似一致，允许确定基质/沉淀物界面自由能和溶质扩散系数。在300 ℃下，由于Sc引起的α-Al/Al-3（Sc 1-xErx）界面自由能是α-Al/Al 3Sc的约两倍大。Er在三元合金中的扩散率比Er在二元Al-0.045at.%中的扩散率小约三个数量级Er的扩散系数比Sc在Al-Sc二元合金中的扩散系数小两个数量级，Sc的扩散系数与文献值基本一致。(C)2009 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The coarsening kinetics of nanoscale, coherent Al-3(Sc1-xErx) precipitates in alpha-Al during aging of a supersaturated Al-0.06 Sc-0.02 Er (at.%) alloy at 300 degrees C are studied using transmission electron microscopy and local-electrode atom-probe tomography. Erbium and Sc segregate at the precipitate core and shell, respectively. The matrix supersaturations of Er and Sc, as well as the mean precipitate radius and number density evolve in approximate agreement with coarsening models, allowing the determination of the matrix/precipitate interfacial free energy and solute diffusivities. At 300 degrees C, the alpha-Al/Al-3 (Sc1-xErx) interfacial free energy due to Sc is about twice as large as for alpha-Al/Al3Sc. The diffusivity of Er in the ternary alloy is about three orders of magnitude smaller than that of Er in binary Al-0.045 at.% Er and about two orders of magnitude smaller than the diffusivity of Sc in binary Al-Sc. The measured Sc diffusivity is consistent with the literature values. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.