钛预合金化共晶铝硅合金组织的细化条件

The Refinement Conditions of Microstructure of Ti Pre-alloying Eutectic Al-Si Alloy

以钛预合金化电解低钛铝合金为母材配制共晶铝硅合金ZL108Ti，研究了其组织细化的条件。结果表明：当钛含量为0．10％～0.13％时，合金表现出了较佳的组织细化效果和良好的力学性能。α-Al二次枝晶臂间距为16．71μm，共晶硅颗粒直径为2．69μm，室温和300℃抗拉强度比不含钛的ZL108分别提高了5％和10％。组织细化机理主要是均匀弥散分布的溶质钛提供了足够的成分过冷，激发潜在强有力的形核相大量非均质形核，以及钛元素抑制晶粒长大的作用。

The electrolytic low titanium Al-based alloy of Ti pre-alloying was used as raw material for producing the eutectic Al-Si ZL108Ti alloy. The refinement conditions of microstructure were studied. When Ti content was 0. 10%-0. 13wt%, effective refinement and high mechanical properties were obtained. The second dendrite arm spacing（DAS） of orAl was 16.71μm. The average diameter of the eutectic Si particles was 2. 69μm. Compared with the ZL108 alloy of no Ti addition, the ultimate tensile strength of ZL108Ti at room temperature and 300℃ increased 5% and 10% respectively. The mechanism of microstructure refinement might be described as follows. The sufficient component under-cooling was provided by the solute Ti which distributed uniformly among Al alloys melts. The sufficient component under-cooling activated more probable potential heteronuclei to nucleate the α-Al. Solute Ti could also strongly restrict growth of the grain.