Effect of in-situ formation of AlP on solidification of hypereutectic Al-Si alloy
Effect of in-situ formation of AlP on solidification of hypereutectic Al-Si alloy
复制标题
原位生成AlP对过共晶Al-Si合金凝固的影响
DOI：
10.3139/146.111831
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Guowei Chang
中科院分区：
文献类型：
--
作者：
Shuing Chen;Lei Zhang;Xudong Yue;Guowei Chang
通过在熔体中加入铜磷合金和搅拌后凝固组织的变化规律，研究了原位AlP的形成对Al-20%Si合金凝固过程的影响。搅拌初期，共晶硅明显细化，硅主要以点状存在。在搅拌中期，典型的共晶组织消失，组织由细小的初晶硅均匀分布在α中。将铜磷合金溶解于Al-20%Si合金中搅拌后，形成了许多尺寸接近初生硅临界形核半径的AlP析出物。这些AlP析出物成为初晶硅和共晶硅的形核。初生硅周围的贫硅层为初生硅长大时初生α相的析出提供了必要条件。对于细小的初晶硅，初晶硅之间的距离减小，较低的温度有利于在初晶硅周围形成完整的α环或连续的α相。在共晶过程中，超细AlP使共晶Si相单独形核长大，共晶α相在初生相α的基础上长大，形成离异共晶组织。
The effects of in-situ AlP formation on the solidification process of an Al-20%Si alloy were studied by examining the change law of the solidification microstructures after the addition of Cu–P alloy to the melt and stirring. During the early stage of stirring, the eutectic Si was clearly refined and Si mainly existed in a point-like shape. During the middle stage of stirring, the typical eutectic microstructure disappeared, and the microstructure consisted of fine primary Si uniformly distributed in the α matrix. Many AlP precipitates with sizes near the critical nucleation radius of primary Si were formed after the Cu–P alloy was dissolved in the Al-20%Si alloy and stirred. These AlP precipitates became the nuclei of the primary and eutectic Si. The Si-poor layers around the primary Si provided the conditions necessary for the precipitation of the primary α phases when the primary Si grew. For finer primary Si, the distance between the primary Si was reduced, and lower temperature facilitated the formation of a complete α loop or continuous α phases around the primary Si. During the eutectic reaction, the ultrafine AlP caused the eutectic Si phases to nucleate alone and grow; the eutectic α phases grew based on the primary α phases, which resulted in the formation of divorced eutectic microstructures.