硼对亚共晶Al-Si合金的细化作用

Refining effect of boron on hypoeutectic Al Si alloys

利用ＤＳＣ，ＳＥＭ 和Ｘ 射线衍射等手段， 分析了硼对纯铝及亚共晶ＡｌＳｉ 合金的细化作用。发现在纯铝中， ＡｌＢ２ 分布在铝的晶界上， 无细化作用； 而在ＡｌＳｉ 合金中， ＡｌＢ２ 具有细化α（Ａｌ） 晶粒的性能。分析认为， 在ＡｌＳｉ 加硼的熔体中， ＡｌＢ２ 虽不能作α（Ａｌ） 的核心， 但它为Ｓｉ 的析出提供形核衬底，随温度的下降， α（Ａｌ） 在Ｓｉ 相上形核， 达到细化的目的。

Refining effect of boron on the hypoeutectic Al Si alloys and pure aluminum has been studied with SEM and XRD. The results indicate that in pure aluminum AlB 2 segregates on the grain boundary without refining effect; and in Al 7Si alloys AlB 2 compound can refine α (Al) grains. In Al Si melt added boron melt, although AlB 2 does not take part directly in the nucleation process, it provides a substrate for nucleation of silicon on which subsequently nucleates α (Al) with the decrease of temperature. Refining effect of boron on the hypoeutectic Al Si alloys and pure aluminum has been studied with SEM and XRD. The results indicate that in pure aluminum AlB 2 segregates on the grain boundary without refining effect; and in Al 7Si alloys AlB 2 compound can refine α (Al) grains. In Al Si melt added boron melt, although AlB 2 does not take part directly in the nucleation process, it provides a substrate for nucleation of silicon on which subsequently nucleates α (Al) with the decrease of temperature.