Eutectic Growth Behavior of Al-7Si Alloy during Directional Solidification

Wu Jiwen; Deng Shaozhen; Tan Fengliang; Li Cai; Wang Li; Wei Xiang

doi:10.15980/j.tzzz.2022.02.016

Views : 0 下载量: 217 CSCD: 0

PDF
Export
Share
Collection
Album

Eutectic Growth Behavior of Al-7Si Alloy during Directional Solidification
Vol. 42, Issue 2, Pages: 209-214(2022)
Published： 2022 ，
DOI： 10.15980/j.tzzz.2022.02.016

扫描看全文

Wu Jiwen, Deng Shaozhen, Tan Fengliang, et al. Eutectic Growth Behavior of Al-7Si Alloy during Directional Solidification. [J]. Special Casting & Nonferrous Alloys 42(2):209-214(2022)
DOI：

Wu Jiwen, Deng Shaozhen, Tan Fengliang, et al. Eutectic Growth Behavior of Al-7Si Alloy during Directional Solidification. [J]. Special Casting & Nonferrous Alloys 42(2):209-214(2022) DOI： 10.15980/j.tzzz.2022.02.016.

摘要

研究了未变质及Sr变质Al-7Si合金定向凝固下的共晶生长行为。未变质Al-7Si合金中的共晶Si组织随着定向凝固生长速度增加呈现不同的形貌，低生长速度（R=2μm/s）下，同一中心辐射的板片状共晶Si交织成“星状”形貌，中等生长速度（R=20μm/s）时，层片状共晶Si呈“小麦束”交织形貌，而高速淬火时，淬火纤维态共晶Si构成“珊瑚状”形貌，此3种不同生长速度下的不同形貌对应有不同的共晶Si生长和分枝机制；Sr变质后，细化的共晶Si呈“珊瑚状”形貌，这可能是“杂质促发孪晶机制”和{111}

面的光滑生长向粗糙生长转变共同作用的结果。

Abstract

The eutectic growth behavior of unmodified and Sr modified Al-7 Si alloy was investigated. The eutectic Si in unmodified Al-7 Si alloy presents different morphologies with the increase of growth speed of directional solidification. At low growth speed of 2 μm/s

the flat plate eutectic Si sharing a center is interweaved into “star” morphology

and the lamellar eutectic Si has a “Wheatsheaf” morphology when the growth speed increased to a medium speed of 20 μm/s

while the quenched fibrous eutectic Si has a “Coral” morphology at high quenched speed. The different morphologies of eutectic Si at different growth speeds correspond to different growth and branching mechanisms. The Sr modified refined eutectic Si has a “Coral” morphology

which could be attributed to the synergy of the“Impurity-induced twinning mechanism”and the transition of {111}

plane from smooth growth to rough growth.